With regard to the length of the basket, there are 3 types of sludge traps:
К – short Lк = 250 mm – for use in combination with a chisel;
С – average Lк = 500 mm – for use in combination with a router;
Д – long Lк = 750 mm – for use in combination with a router.

By type of connecting threads:
top – coupling, bottom – nipple (MH);
top – nipple, bottom – sleeve (HM);
top and bottom – sleeve (MM);
top and bottom – nipple (НН).