The Shortie Patch is 150 ml. You may need to fill in a broken wall or do a cosmetic job that does not require the 420 ml Pro system. Use as much or as little as you need, replace the cap and store the rest in a cool place until next time. The Shortie is the same chemical make-up as the Pro Slow Patch but is 150 ml in size. It uses an adapter enabling you to use a standard caulking gun. Use of the Pro tip is suggested. Set time is 4-6 minutes. Use in a well-ventillated area or see our safety equipment.