Wielands fasis duo earth din blocks wkfn d12sl35 greenyellow wieland 5670491550 wielands greenyellow fasis duo earth din block wkfn 4 d22sl35 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 an 800v ra