IS-CP4-PB Push Button Manual Call Point The IS-CP4-PB push button manual call points are designed for the harshest of environments and approved for Zones 0, 1, 2, 21 & 22 requiring hazardous area intrinsically safe equipment for the control of fire and gas alarm systems. SIL2 compliant to IEC61508 (2010). The IS-CP4 range features enclosures manufactured from corrosion proof, marine grade, copper free LM6 (A413) aluminium which is chromated and powder coated. Available with and without monitoring resistors all versions are certified to IECEx and ATEX standards with additional INMETRO and Ex EAC approvals. The push button mechanism is protected by a spring loaded cover therefore the switch requires a two-action activation. The IS-CP4-PB is user re-settable by rotating the push button.