Wieland fasis feed through din blocks wkfn 35 bluegrey wieland 5670600550 wielands grey fasis feed through din block wkfn 635 is a terminal block for mounting onto a ts 35 din rail and has been given an approved atex rating for use in various zones the secure and maintenance free tension spring clamp remains simple to operate via a standard screwdriver which can be held securely in the terminal for optimal handling while connecting wires the block has a 41a current rating 800v rated