These are the 10-12 gauge double sided crimp on connectors.  

Single wire needs to be folded over so it is double up in the connector end and two wires twisted together so they slide easily in to the connector for secure fittings. 

Each element has two connectors.  There are typically 12 in a 3 section kiln.  With new Skutt Brand Elements 2 connectors plus element pins and new porcelain insulators are included with each element package. 

These can be used to replace burnt up screw on connectors on older models or on Amaco Excel kilns and any other kiln using 10-14 gauge wires to connect elements to their feeder wires.