They'll be marketed as "reduced back pressure" or "flow through" suppressors. They do noticeably reduce gas blowback at the expense of noise reduction. Usually it's a few decibel depending on design for much less gas, very worthy trade off for semi auto firearms. Zero use on a bolt gun.
More or less if it's a newer suppressor and it's 3d printed it's a flow through suppressor. The bt I mentioned is a flow through, as well as being a hybrid titanium/inconel design so it's light weight yet extremely rugged if you ever feel the need to dump 5-6 mags of 7.62 through it in a few minutes. You really cant beat that for the price.