DSI Underground’s Friction Bolt is manufactured from a high-strength steel tube with a slot along its entire length. A ring, or collar, is welded on the outer end to hold a domed plate to the rock surface, offering ground support with fast installation times and low-profile protrusion from the rock face.
For more Information: https://www.dsiunderground.com.au/products/mining/rock-bolts/friction-bolts/friction-bolt-33mm