3 Pack of refills for the Pilot Frixion Synergy Knock. This refill has the Synergy Tip, the hybrid needle-nose conical tip that ensures smooth writing with the finest of tip sizes. Available in your choice of blue, black, or red, now in 3 tip sizes! Each refill set includes 3 refills. If you’re looking for more color options, check out the single refill packs that are available. These refills are also compatible with pens such as the Frixion Synergy Knock Biz Marble and Frixion Point Knock.