The S153A is a rugged Fusion Splicer using Active Clad Alignment technology. Active Clad Alignment technology utilizes 3 axis (X Y & Z) alignment in a similar way as Core Alignment Fusion Splicers do. The S153A Active Clad Alignment fusion splicer is much more resilient to Dirty V-Grooves and curved / bent fiber which could pose problems to conventional Clad Alignment Fusion splicers.