diff --git a/constants/battle_tower_constants.asm b/constants/battle_tower_constants.asm
index ad119ddaa..852ebf297 100755
--- a/constants/battle_tower_constants.asm
+++ b/constants/battle_tower_constants.asm
@@ -45,10 +45,7 @@ BATTLETOWER_NROFPKMNS EQU 3
 BATTLETOWER_NROFTRAINERS EQU 7
 
 BATTLETOWER_NUM_UNIQUE_TRAINERS EQU 70
-BATTLETOWER_TRAINER_MASK EQU %1111111
-
 BATTLETOWER_NUM_UNIQUE_PKMN EQU 21
-BATTLETOWER_PKMN_MASK EQU %11111
 
 BATTLETOWER_TRAINERDATALENGTH EQU $24
 BATTLE_TOWER_STRUCT_LENGTH EQU $e0 ; NAME_LENGTH + BATTLETOWER_NROFPKMNS * (PARTYMON_STRUCT_LENGTH + PKMN_NAME_LENGTH) + BATTLETOWER_TRAINERDATALENGTH
diff --git a/engine/events/battle_tower/load_trainer.asm b/engine/events/battle_tower/load_trainer.asm
index 08571dcef..67c9d2232 100644
--- a/engine/events/battle_tower/load_trainer.asm
+++ b/engine/events/battle_tower/load_trainer.asm
@@ -27,12 +27,12 @@ Function_LoadOpponentTrainerAndPokemons: ; 1f8000
 	add b
 	ld b, a ; b contains the nr of the trainer
 if DEF(_CRYSTAL11)
-	and BATTLETOWER_TRAINER_MASK
+	maskbits BATTLETOWER_NUM_UNIQUE_TRAINERS
 	cp BATTLETOWER_NUM_UNIQUE_TRAINERS
 else
-; Crystal 1.0 used the wrong constants here, so only the first 21
+; Crystal 1.0 used the wrong constant here, so only the first 21
 ; trainers in BattleTowerTrainers can be sampled.
-	and BATTLETOWER_PKMN_MASK
+	maskbits BATTLETOWER_NUM_UNIQUE_PKMN
 	cp BATTLETOWER_NUM_UNIQUE_PKMN
 endc
 	jr nc, .resample
@@ -115,7 +115,7 @@ Function_LoadRandomBattleTowerPkmn: ; 1f8081
 	ld a, [hRandomAdd]
 	add b
 	ld b, a
-	and BATTLETOWER_PKMN_MASK
+	maskbits BATTLETOWER_NUM_UNIQUE_PKMN
 	cp BATTLETOWER_NUM_UNIQUE_PKMN
 	jr nc, .resample
 	; in register 'a' is the chosen Pkmn of the LevelGroup