"I needed some SAE 30 ('Straight 30') oil for my compressor but did not need too much as the sump holds only 250ml ish; too little to make purchasing a 5 litre can @ 25 quid but ideal for this medium grade oil available in 1 litre cans.
I got a second bottle so have plenty in reserve.
Compressor users take heed:
Please do check oil reservoir regularly; your failure to so do may culminate in some unwelcome noises, smells and crashes... sometimes terminal! :("