Arrow T50 Series top quality 0.050 wire staples to suit:
T50, T55, T50PBN, HT50P (up to 12mm only), HTX50, ETFX50, ETF50PBN, CT50K, 5700 AND 8000.

The Arrow ARRT5012S T50 Staples Box contains top quality 0.050 wire staples for use with T50 and T55 tackers:

These stapes can be used for canvas, roofing paper, vapor barrier etc. with the following specifications:
Size: 1/2 inch / 12mm
Qty: 1250 staples