NOS Bulova Factory Mainspring 11AAC 11ABC 11AC 11ACC 11AERC  11AF 11AFC 11ALD 10AN 11AL 10BEAC 10BNCH 10BZC 7BEAC 7BPC 7BUC 5AT 5AZ

These are Bulova factory mainsprings made of alloy metal. Most of them are in the inserter packs for easy installation. These calibers also fit other calibers. Please check to make sure that it will fit yours. These are out of the shop I used to own. I hope that these will be useful for restoring old-time pieces for you . Keep checking with us because I will be posting more parts.