Air Locker 20 Gauge 5/8″ Long T50 Fine Wire Stapler, U641. Upholstery Stapler is an easy to use pneumatic stapler with plenty of useful features. It uses standard 20-gauge T50 fine wire staples to get the job done right. The high-capacity bottom-load magazine handles 100 staples. The U641 stapler requires 60-100 PSI air pressure, so it will work with most air compressors. Comes in a Blow Molded Case.