Feature: 1. These pen adpateres can replace stock pen holder to allow use of other most popular markers and pens (Sharpie/Bic/Crayola/Sakura/Pilot/Pentel/Paper Mate/Mitsubishi uni-Ball) in your machine. 2. Compatible with machine such as Explore Air, Air 2, Air 3, Maker and Maker 3. 3. Each color represents a different fit model, which you can easily identify by the number on cover. 4. Depth calibration is not required as the adapter perfectly aligns each pen/mark for precise height and point center. 5. Made of premium ABS plastic material, durable and easy to install and use. Specification: Features: These pen adpateres can replace stock pen holder to allow use of other most popular markers and pens (Sharpie/Bic/Crayola/Sakura/Pilot/Pentel/Paper Mate/Mitsubishi uni-Ball) in your machine. Compatible with machine such as Explore Air, Air 2, Air 3, Maker and Maker 3. Each color represents a different fit model, which you can easily identify by the number on cover. Depth calibration is not required as the adapter perfectly aligns each pen/mark for precise height and point center. Made of premium ABS plastic material, and easy to install and use. Specification: Material: ABS Plastic Quantity: 17pcs Package Size: 10x15cm/4 x 5.9in Package Weight: 55g/1.9oz Packing List: 17 x Pen Adapter Package List: 17 x Pen Adapter