What it defines
A 3/8-16 UNC screw, described with 1/4-20 in ISO 1222.
What it does not promise
A thread is not a load rating.
Where it turns up
The SIRUI P-326 has a reversible 1/4-20 and 3/8-16 screw; the SmallRig CT-10 lists both; sliders such as the Andoer 12-inch offer 3/8-inch holes.
How to check before buying
Match the thread of the head you plan to use, and keep an adapter in the bag.
What people ask before they commit
Where is 3/8-16 used?
Between tripod legs and heads, on light stands, sliders and some monopods.
Can I mount a camera directly on 3/8-16?
Not without an adapter; cameras use 1/4-20.
Are adapters reliable?
Yes, but small adapters are easy to lose; reversible screws avoid that.
Last reviewed November 2, 2026