InkOwl Toner Refill Kit for BROTHER TN-331, TN-336 (Black, 1-Pack) Includes 1 bottle of Ink Owl premium formulation toner, 1 spout for easy pouring, easy-seal tape, and detailed, graphic instructions. BROTHER cartridges are easy to refill thanks to a toner plug on the side of the cartridge. Easy-seal tape is included in case the plug does not offer a good enough seal after being removed and put back in. Our instructions will guide you step-by-step through the entire refill process. Includes enough toner powder for 4000 pages at 5% page coverage. This is the same yield as the original BROTHER TN-336 high-yield cartridge. IMPORTANT: If the cartridge you're going to refill is the original cartridge (the starter cartridge) that shipped with your printer, you will also need to purchase a flag gear kit.