Accu-Tac HD-50, Bipod, Black HD50-ASQD The HD-50 Arca Spec QD was designed for the 50 BMG cal platforms or for heavy ELR style rifles. This is their Heavy Duty and most robust bipod. The arm lock lugs are larger to withstand the heavy recoil of a 50 BMG. This bipod has the ability to cant and has a very sturdy throw lever. The lever allows you to adjust the tension and enhance the ability to lock the canting motion into place. It is also adjustable so it can be repositioned to tuck away or to adjust the tension once you hit a stop. The legs can be extended into nine different height options and can be positioned in the forward stowable position or 90 degree straight down. Its wide center hub delivers more stability" strength" and support.