It's like a fuzz face, but more practical. The buffer switch takes it from fuzz to a more tame distortion-type effect and is meant to help when pairing it with a wah. There's a lot to like here, it cranks out the classic 70s style fuzz with gleeful abandon.

Model: MXR M173 Classic 108 Fuzz
Made in: USA, recent model 
Type: fuzz
Power: regular 9v negative supply
Equivalent new street price (approx): $220aud
Mods: velcro added
Accessories: original box and docs
Condition notes: minor marks only, excellent condition