You'll find them listed as "potentiometers" in catalogs, specifically as printed circuit board mounted trimmer potentiometers or some such thing. For what you have, about the only thing you need to worry about is the value (as opposed to power rating). Unfortunately, yours is smashed, so you can't measure it. If you have the schematic, maybe it will give you the value in ohms, kilohms (K ohms) or megohms (M ohms). Pots (aka potentiometers) tend to have values with either 1 or 5 as the significant digit, e.g., 500 ohms, 100 ohms, 5K ohms, 1M ohm, etc. You're not going to seem something like 60K ohms or 354 ohms.
Physical size will be another consideration since yours is PCB mounted. Digi-Key Corporation and Mouser Electronics are excellent sources for electronics parts here in the U.S.