DuraSight™ Z2 Alloy Integral Ring/Base Design is the ultimate in terms of strength and ease of installation. The base and the lower ring are all one unit and are formed in a mold with Z-2 Alloy. This new system eliminates one of the key weaknesses of traditional two-piece systems. The strength and cosmetic appeal of the Z-2 integrated system is far superior to any aluminum system on the market and yet the price is very reasonable. Fits all CVA In-Lines Traditions In-Lines Winchester In-Lines and T/C Encore Omega Triumph.