Boker USA Multi-Purpose Pen w/Glass Breaker Tip B. Specifications for Boker USA Multi-Purpose Pen w/Glass Breaker Tip: Manufacturer: Boker USA Fabric/Material: Aluminum Features of Boker USA Multi-Purpose Pen w/Glass Breaker Tip: Material: Aluminum Pen Color: Gray Diameter: .55 inch Length: 5.91 inch Weight: 1.41 ounce Package Contents: Boker Multi-Purpose Tactical Pen with Carbide Glass Breaker 09BO091 With this versatile pen you are prepared for anything It not only serves as a high quality writing tool it also features a glass breaker tip in case of emergency and can be used as a kubotan for self defense. The sturdy clip keeps it readily accessible at all times and the screwed on cap prevents accidental separation. The deep finger grooves provide superior comfort. To change the ink cartridge simply unscrew the pen counter clockwise to prevent accidental disassembly. Compatible with Fisher Space Pen cartridge #PR4 which can be purchased at www.spacepen.com. Diameter (cap): 13.9mm. Overall length: 6. Weight: 1.4 oz.