Their classification system is much different. They use numbers to place competitors in classes. 0-550 is for the lowest class, 551-1000 puts you in the 2nd tier, 1001-2000 is the 3rd, 2001-3000 is the 4th and anything above that or anyone not using fuses automatically ends up in the highest classes. They go by cone area and fuse rating (x10). So using two 18s (508.9 sq. inches) I am allowed to use 40 amps of fusing (40 x 100 = 400) for classes Street2, Mod2 and DB2. I can step up to 140 amps of fusing for Street3, Mod3 and DB3. Anything above 140 and below 240 would put me in Street4, Mod4 or DB4. If you do not use fusing, you're automatically entered into Street5, Mod5 or DB5. So, the three of us (Steve, Jon and myself) could all be in the same Park and Pound (DB3) class IF Jon ran say 160amps of fusing, Steve used 120amps of fusing and I used 140amps of fusing. It seems a bit confusing but once you figure out the formula, it's pretty easy.