TK Trailer Kits (BOAR Series) 2k Single Axle TK Trailer kit - 2000 lb Capacity (Original Series) $599.99. 3500 lb Light Duty Single Axle TK Trailer Kit - 3.5K Capacity (Original Series) $599.99. 3500 lb Heavy Duty Single Axle TK Trailer Kit - 3.5K Capacity (Original Series) Regular price. $779.99.