Just google the name of the tool you wrote as the subject title for this thread and you could have found this information.
Yes its a roofing nailer. Nail length capacity 3/4- to 1-3/4-inch galvanized roofing nails.
BOSTITCH RN45B-1
Old amazon link for it:
https://www.amazon.com/dp/B0000225IV/?tag=atomicindus08-20
Product description
688-RN46-1 Features: -Cartridge Cap.: 120 [Max]. -Operating Pressure: 70.0 psi [Min], 100.0 psi [Max]. -Operating Type: Contact Trip (Nose Contact Activated). -Impact: 420.00 in lb. Type of Nailer: -Roofing Nailers. Type of Fastener: -Roofing Nails/Nail Coils. Fastener Size Range: -.5" - 1.25"/1.25" - 2.5". Generic Dimensions: -Nail Length: 3/4 in [Min], 1 3/4 in [Max]. -Height: 10 5/8 in. -Length: 10 7/8 in. -Width: 4 5/8 in. Dimensions: Overall Height - Top to Bottom: -10.625 Inches. Overall Width - Side to Side: -4.625 Inches. Overall Product Weight: -5.8 Pounds.
From the Manufacturer
This coil roofing nailer drives fasteners with increased range, from 3/4- to 1-3/4-inch galvanized roofing nails. It is lightweight and well balanced at only 5.96 pounds. Features include a shingle placement guide, long-life carbide-steel contact parts, a new comfort-grip handle, and fast, easy, one-piece, one-step loading. This nailer is excellent for asphalt shingling, insulation board, vinyl siding, fiber cement roofing, and siding. Fitting not included.