The button battery holder has a switch function, no switch is required. Battery holder with cover, safe and anti-short circuit. The use of good quality materials and with impact resistance. Tip: Flip the front side up, the left line is positive, the right line is negative. (red line is positive, black line is negative; gold line is positive, silver line is negative) Specifications: Material: Plastic + Metal Dimensions: 3 x 2.3 cm; 5 x 2.3 cm Color: White Packaged Included: 10 x Battery Holders