Check the listing for details. Ronstan Single & Becket Tube Rivet Head - Series 29. Condition: New. Listed at 23.34 USD. Stainless steel cheeks and Acetal sheaves ensure a long service life with virtually no maintenance. Hollow rivets accept fixing screws, shackles or can be used as a becket for extra purchase. U.V. stabilised Acetal sheaves Grade 316 stainless steel cheeks Lightweight durable construction Economical Maintenance free Sheave Ø - 30 mm Max. Rope Ø - 8 mm M.W.L.