Compression, but it's been compressed... size-wise. It's now very tiny. But, it will make your clean tone sound huge... metaphorically. 

Model: TC Electronic HyperGravity Mini
Made: China, 2022 
Serial: S220500213CQ8
Type: compressor
Power: standard 9v DC negative power supply (not included)
Equivalent New Street Price (Approx): N/A
Mods: none
Accessories: original box and manual

Condition Notes: used, no major marks. Tested and fully functional.
Overall: excellent condition (9/10)