The DM1 is a truly minimalist design. Made from a single piece of aluminum, cut into the ideal shape to positively retain as few as 1 and up to 4 (4-Card model), 8 (8-Card model) or 12 (12-Card model) identification or credit cards. The design eliminates any unnecessary parts, but securely and beautifully carries and protects your cards. It does NOT block RFID - so you can use building access cards and contact-less RFID credit cards without removing them from the DM1. The open front and back are ideal for photo ID cards like a drivers license. At only 3.53" x 2.38" x 0.23", the 4-Card model is thinner than an iPhone 6 and just barely larger than a credit card. Our products are CNC Machined in the USA from a single billet of 6061-T6 Aircraft-Grade Aluminum. There are no screws, hinges, snaps, magnets, straps or rubber bands to break. When you insert cards, a positive click reassuringly confirms that your cards are fully and securely inserted. At only 12 grams, the 4-Card model might be the lighest wallet you can buy!