KR-1/Ø25-M18 and KR-2/Ø25-M18 expansion shells of ø25 mm diameter are elements fixing the bolt in the hole. KR-1/Ø25-M18 shell consists of one shell sleeve and one expander, while KR-2/Ø25-M18 shell consists of two shell sleeves and two expanders.
The bolt rods are made of plain AP 600 steel bar of ø18.3 mm in accordance with ZN-97/AP-2 standard. The rods vary in terms of shape and size of the forged head. The upper part of the rod ends with a rolled M18 thread.