TYPE 4 MULTI-VARIABLE STEAM STRIPS - box of 250 dual strips Type 4 multi-variable steam indicator strips are designed to be used in steam sterilizers operating at 134° C - 3.5 min. The indicator strips will provide assurance of steam penetration into the packs. The water based, non-toxic chemical indicator in compliance with ISO 11140-1 will show a clear colour change from blue to black after successful steam sterilization. Test indicator strips are cost effective and can be divided into two separate pieces for economical use.