SA Fustat Fuse Adapter for Using Type S and SL Rejection Plug Fuses In Edison Base Fuse Sockets. The size-rejection SA inserts convert an Edison Base receptacle to accept the Rejection Base S and SL fuses. Once installed, the SA adapter can not easily be removed and limits the amp rating of the fuse that can be installed. SA adapters are available in a wide variety of sizes to protect motors and branch circuits. Use the chart to select the correct SA adapter. Ideal for retrofitting Edison Base fuse panels in rental property to prevent over-fusing and bring existing panels up to compliance with the NEC.