The Arrow ARRT50516S T50 Staples Box contains top quality 0.050 wire staples for use with T50 and T55 tackers:

These stapes can be used for roofing felt, housewrap, upholstery, valances, headboard coverings, shelving, etc. with the following specifications:
Size: 5/16 inch / 8mm
Qty: 1250 staples