Sterile, disposable, and sharp with easy grip 1.3" x 0.25" dia plastic body. Use alone or with the Auto-Lancet. The 0.1" long needle, protected by a twist-off plastic cap, gives controlled depth penetration. Available in 21, 23, 25, 26, 28 and 30 gauges. The 21 gauge Ject contains 100 needles. All other gauges contain 200 needles.