JK250 series of resettable fuse is a kind of overcurrent protection unit which specially designed and manufactured for the communication exchanger and distributing frame. Has passed the repeated selective examination by the product protectionTesting Centre of the Ministry of Information Industry and the Bureau of Technical Supervision, this series' product performance completely conform to the standards of the telecommunications and posts industry.

The JK250 series' rated operating voltage is 250v, the holding current being 20mA to 2A. There are 21 types of this series.