Milwaukee 7120-21 3/4 to 1-3/4″ Coil Roofing Nailer for $159.99 shipped. Here is a screenshot for your reference. It has an operating pressure of 70 PSI to 120 PSI, 15-degree collation angle, and 120 nail magazine capacity. Note that 30 out of 34 reviews have given it a full 5/5 rating. As a comparison, Home Depot has it for over $300.