Today I have two hunting rifle bipods from Twod, they are almost identical in design. The difference is size. The one pictured on the left of the screen is adjustable from 9-13 inches. The bipod on the right of the screen adjusts from 6-9 inches.
The smaller version is cheaper. It is $15.99 on Amazon, with its big brother costing $19.99.
Both bipods attach to a sling swivel stud, something I have a hard time saying fast. If your rifle does not have an attatched stud, but it has a rail the rifle bipods each come with a rail mount adapter.
Both are constructed of black anodized aluminum and are pretty sturdy.
I have had several of these type bipods over the years and for the price they are hard to beat.