diff --git a/src/items/held-items/accuracy-booster.ts b/src/items/held-items/accuracy-booster.ts
index 6ecbc883c26..fde2a06d351 100644
--- a/src/items/held-items/accuracy-booster.ts
+++ b/src/items/held-items/accuracy-booster.ts
@@ -15,7 +15,7 @@ export class AccuracyBoosterHeldItem extends HeldItem {
 
   private accuracyAmount: number;
 
-  constructor(type: HeldItemId, maxStackCount = 1, accuracy: number) {
+  constructor(type: HeldItemId, maxStackCount: number, accuracy: number) {
     super(type, maxStackCount);
     this.accuracyAmount = accuracy;
   }
diff --git a/src/items/held-items/attack-type-booster.ts b/src/items/held-items/attack-type-booster.ts
index 3e102527d49..aad80b3c1d0 100644
--- a/src/items/held-items/attack-type-booster.ts
+++ b/src/items/held-items/attack-type-booster.ts
@@ -46,7 +46,7 @@ export class AttackTypeBoosterHeldItem extends HeldItem {
   public powerBoost: number;
 
   // This constructor may need a revision
-  constructor(type: HeldItemId, maxStackCount = 1, moveType: PokemonType, powerBoost: number) {
+  constructor(type: HeldItemId, maxStackCount: number, moveType: PokemonType, powerBoost: number) {
     super(type, maxStackCount);
     this.moveType = moveType;
     this.powerBoost = powerBoost;
diff --git a/src/items/held-items/base-stat-booster.ts b/src/items/held-items/base-stat-booster.ts
index 72428a2d572..8ca87da7732 100644
--- a/src/items/held-items/base-stat-booster.ts
+++ b/src/items/held-items/base-stat-booster.ts
@@ -36,7 +36,7 @@ export class BaseStatBoosterHeldItem extends HeldItem {
   public effects: HeldItemEffect[] = [HeldItemEffect.BASE_STAT_BOOSTER];
   public stat: PermanentStat;
 
-  constructor(type: HeldItemId, maxStackCount = 1, stat: PermanentStat) {
+  constructor(type: HeldItemId, maxStackCount: number, stat: PermanentStat) {
     super(type, maxStackCount);
     this.stat = stat;
   }
diff --git a/src/items/held-items/base-stat-total.ts b/src/items/held-items/base-stat-total.ts
index ecce12dca41..c862d56e176 100644
--- a/src/items/held-items/base-stat-total.ts
+++ b/src/items/held-items/base-stat-total.ts
@@ -18,7 +18,7 @@ export class BaseStatTotalHeldItem extends HeldItem {
   public isTransferable = false;
   public statModifier: number;
 
-  constructor(type: HeldItemId, maxStackCount = 1, statModifier: number) {
+  constructor(type: HeldItemId, maxStackCount: number, statModifier: number) {
     super(type, maxStackCount);
     this.statModifier = statModifier;
   }
diff --git a/src/items/held-items/crit-booster.ts b/src/items/held-items/crit-booster.ts
index e6e264f9867..10bf5f0b1dd 100644
--- a/src/items/held-items/crit-booster.ts
+++ b/src/items/held-items/crit-booster.ts
@@ -22,7 +22,7 @@ export class CritBoostHeldItem extends HeldItem {
   /** The amount of stages by which the held item increases the current critical-hit stage value */
   protected stageIncrement: number;
 
-  constructor(type: HeldItemId, maxStackCount = 1, stageIncrement: number) {
+  constructor(type: HeldItemId, maxStackCount: number, stageIncrement: number) {
     super(type, maxStackCount);
 
     this.stageIncrement = stageIncrement;
@@ -50,7 +50,7 @@ export class SpeciesCritBoostHeldItem extends CritBoostHeldItem {
   /** The species that the held item's critical-hit stage boost applies to */
   private species: SpeciesId[];
 
-  constructor(type: HeldItemId, maxStackCount = 1, stageIncrement: number, species: SpeciesId[]) {
+  constructor(type: HeldItemId, maxStackCount: number, stageIncrement: number, species: SpeciesId[]) {
     super(type, maxStackCount, stageIncrement);
 
     this.species = species;
diff --git a/src/items/held-items/evo-tracker.ts b/src/items/held-items/evo-tracker.ts
index 851b1f8c7ec..9aa397bb421 100644
--- a/src/items/held-items/evo-tracker.ts
+++ b/src/items/held-items/evo-tracker.ts
@@ -18,7 +18,7 @@ export class EvoTrackerHeldItem extends HeldItem {
   protected required: number;
   public isTransferable = false;
 
-  constructor(type: HeldItemId, maxStackCount = 1, species: SpeciesId, required: number) {
+  constructor(type: HeldItemId, maxStackCount: number, species: SpeciesId, required: number) {
     super(type, maxStackCount);
     this.species = species;
     this.required = required;
diff --git a/src/items/held-items/exp-booster.ts b/src/items/held-items/exp-booster.ts
index f817aafbbcf..4c38398e78b 100644
--- a/src/items/held-items/exp-booster.ts
+++ b/src/items/held-items/exp-booster.ts
@@ -16,7 +16,7 @@ export class ExpBoosterHeldItem extends HeldItem {
   private boostPercent: number;
   private boostMultiplier: number;
 
-  constructor(type: HeldItemId, maxStackCount = 1, boostPercent: number) {
+  constructor(type: HeldItemId, maxStackCount: number, boostPercent: number) {
     super(type, maxStackCount);
     this.boostPercent = boostPercent;
     this.boostMultiplier = boostPercent * 0.01;
diff --git a/src/items/held-items/flinch-chance.ts b/src/items/held-items/flinch-chance.ts
index d90dd7ade41..a8b65aa0db5 100644
--- a/src/items/held-items/flinch-chance.ts
+++ b/src/items/held-items/flinch-chance.ts
@@ -19,7 +19,7 @@ export class FlinchChanceHeldItem extends HeldItem {
   public effects: HeldItemEffect[] = [HeldItemEffect.FLINCH_CHANCE];
   private chance: number;
 
-  constructor(type: HeldItemId, maxStackCount = 1, chance: number) {
+  constructor(type: HeldItemId, maxStackCount: number, chance: number) {
     super(type, maxStackCount);
 
     this.chance = chance; // 10
diff --git a/src/items/held-items/item-steal.ts b/src/items/held-items/item-steal.ts
index 26ae198c46e..f9dce8cc75b 100644
--- a/src/items/held-items/item-steal.ts
+++ b/src/items/held-items/item-steal.ts
@@ -15,7 +15,7 @@ export interface ItemStealParams {
   target?: Pokemon;
 }
 
-//  constructor(type: HeldItemId, maxStackCount = 1, boostPercent: number) {
+//  constructor(type: HeldItemId, maxStackCount: number, boostPercent: number) {
 
 /**
  * Abstract class for held items that steal other Pokemon's items.
@@ -129,7 +129,7 @@ export class ContactItemStealChanceHeldItem extends ItemTransferHeldItem {
   public readonly chancePercent: number;
   public readonly chance: number;
 
-  constructor(type: HeldItemId, maxStackCount = 1, chancePercent: number) {
+  constructor(type: HeldItemId, maxStackCount: number, chancePercent: number) {
     super(type, maxStackCount);
 
     this.chancePercent = chancePercent;
diff --git a/src/items/held-items/stat-booster.ts b/src/items/held-items/stat-booster.ts
index 71647cb821b..43a655b364d 100644
--- a/src/items/held-items/stat-booster.ts
+++ b/src/items/held-items/stat-booster.ts
@@ -26,7 +26,7 @@ export class StatBoostHeldItem extends HeldItem {
   /** The multiplier used to increase the relevant stat(s) */
   protected multiplier: number;
 
-  constructor(type: HeldItemId, maxStackCount = 1, stats: Stat[], multiplier: number) {
+  constructor(type: HeldItemId, maxStackCount: number, stats: Stat[], multiplier: number) {
     super(type, maxStackCount);
 
     this.stats = stats;
@@ -141,7 +141,7 @@ export class SpeciesStatBoostHeldItem extends StatBoostHeldItem {
 
   constructor(
     type: SpeciesStatBoosterItemId,
-    maxStackCount = 1,
+    maxStackCount: number,
     stats: Stat[],
     multiplier: number,
     species: SpeciesId[],
diff --git a/src/items/held-items/turn-end-status.ts b/src/items/held-items/turn-end-status.ts
index 66abd455886..ae6b9f6dffc 100644
--- a/src/items/held-items/turn-end-status.ts
+++ b/src/items/held-items/turn-end-status.ts
@@ -19,7 +19,7 @@ export class TurnEndStatusHeldItem extends HeldItem {
   /** The status effect to be applied by the held item */
   public effect: StatusEffect;
 
-  constructor(type: HeldItemId, maxStackCount = 1, effect: StatusEffect) {
+  constructor(type: HeldItemId, maxStackCount: number, effect: StatusEffect) {
     super(type, maxStackCount);
 
     this.effect = effect;