The 23-Gauge Pinner
The number in a 23-gauge pinner refers to the diameter of the fastener. The 1/2 inch to one inch fasteners used with this tool can be used to hold pieces of crown molding together at corners, or to assemble picture frames and birdhouses. The fastener creates a barely noticeable hole and is less likely to split thin pieces of wood than a larger nail.
The 18-Gauge Brad Nailer
An 18-gauge brad nailer accepts 5/8 inch to 2 1/8 inch fasteners. That is probably the first tool of this kind that a home woodworker or crafter would buy. The tool has an adjustable depth-of-drive so that you can countersink the fastener.
The 16-Gauge Brad Nailer
A 16-gauge brad nailer takes 1 1/4 inch to 2 1/2 inch straight collation nails with flat t-heads. It also has an adjustable depth-of-drive.
The 15-Gauge Angle Collation Tool
A-15 gauge angle collation tool releases 1 1/4 inch to 2 1/2 inch round-headed nails. This adjustable depth-of-drive tool is angled to allow you to get into corners.
Framing nailers use a special type of nails. They have full round heads in a plastic collation. The full round heads require the fasteners to be spaced a little farther apart than most fasteners used in pneumatic tools. Therefore, a much larger magazine is required to accept the same number of nails.