supply of spd-class d protection device for 24 v ac / dc for signal equipment as per rdso spec no. rdso / spn / 144 / 2014 or latest. it should be of spark gap type with led type indication and din rail mount and shall be of thermal disconnecting type and equipped with potential free contact for remote monitoring. the protection shall be in compliance to iec 61643 with latest amendment. the detailed specification as per rdso recommendation is attached as annexure. other condition: compliance of the parameters mentioned in the specification shall be certified by the firm and attached along with the offer. [ warranty period: 30 months after the date of delivery ] , spd-class d protection device for 110 v ac for signal equipment as per rdso spec no.rdso / spn / 144 / 2014 or latest. it should be of spark gap type with led type indication and din rail mount and shall be of thermal disconnecting type and equipped with potential free contact for remote monitoring. the protection shall be in compliance to iec 61643 with latest amendment. the detailed specification as per rdso recommendation is attached as annexure. other condition: compliance of the parameters mentioned in the specification shall be certified by the firm and attached along with the offer. [ warranty period: 30 months after the date of delivery ]