Extremely practical heavy duty staple gun with 1000pcs D-type 5/16-inch(8 mm) staples included; Size range of applicable staples - D type (T50): 1/4-inch(6 mm), 5/16-inch(8 mm), 3/8-inch(10 mm), 1/2-inch(12 mm), or 9/16-inch(14 mm) Thick steel construction offers durability and minimizes spring-back impact; the steel parts have been hardened in a 1,500-degree furnace for maximum durability The rear-load magazine with jam-resistant mechanism provides a smooth stapling experience; the staple-viewing window takes the guesswork out of knowing when to reload Ergonomic hand slot helps prevent hand fatigue with prolonged use and offers a secure grip Ideal for household and commercial use; upholstery projects, insulation, weather stripping, and much more