This is a Seekins Precision Gas Block, model 0011510065.
The Select Adjustable Gas Block allows a near infinite initial adjustment using an Allen wrench. To begin" simply turn the gas screw in (reducing gas) or out (increasing gas)" whichever you require" and finish by attaching the gas switch for tool-less" on the fly adjustments without losing your initial gas setting.
Features:
40 Position Fine Adjustment
Melonite Coated Tool Steel
Tool-Less Adjustment
