Littelfuse Model ISS-105-ISO-3 3-Channel Intrinsically Safe Only Switch 120VLittelfuse ISS 105 ISO 3 Intrinsically Safe Relay Product Description The ISS 105 is a smart five channel intrinsically safe relay and pump controller. The ISS 105 can be configured for a wide variety of applications including alternating or non alternating duplex, duplex separate pump stop (SPS), triplex and quadplex applications. It can be set up for pump up or pump down applications or can be used as a five channel relay. The ISS 105 has a long