The IS-a105 is a high output, 105db(a) alarm sounder. approvals include aTeX, Iecex and goST-r for zone 0 applications and fm approval for class I division 1 and class I zone 0 applications. The IS- a105 is suitable for all intrinsically safe signalling applications including re, security and process control. The e2S is sounder range is used only for intrinsically safe applications. all the features of the a105 sounder but the added advantages of IS. an IS combination unit is also available and is ideal for areas where an audible/visual alarm is required.