hi there i have 2 new springs i got in a job lot and wondered if you could tell me how low thes can go ie 20mm 30mm 40mm etc , i have searched the net and can't find the answer there and even tried the company site ( Apex) so here is what is written on them ( Apex 80-72002 HA 48/15 ) or could you explain how i can measure them Thanks in advance .