All Adapters fit either 1A2 or S Series bipods.
AR-15, Issue:08, Page:091
Brownells Christmas , Issue:2X, Page:012
Big Book Catalog, Issue:65, Page:358
Law Enforcement / Police Store, Issue:13, Page:013
New Product Supplement, Issue:525, Page:000
SPECS: Aluminum and high carbon steel, anodized, black finish.