There are 6 chips inside the buckle. By controlling the button switch, they share one IC coil or one ID coil, without using batteries. and hold the corresponding button to write or swipe the card. The buckle enter water, but the switch is waterproof, and even if the buckle is submerged in water, it can still be used. UID card: IC card, without firewall function, does not support elevator cards. The advantage is that it supports repeated erasing by all card and is commonly used for access cards. CUID card: Firewall IC card, supporting elevator cards (if not possible, you must use a FUID card to copy, which is related to the firewall settings of the card swiping machine), the most commonly used copy card, can be repeatedly erased. Remember: Before writing data for the second time, the data written for the first time must be cleared first. The method is to first read (unlock) the card, and then format (or clear) the card. Some low-end IDIC handheld devices cannot write CUID cards, please note. If the data contains a lock area code, it is not allowed to erase the card number, as it permanently lock the card. Product Name: Six in One Copy Card Working frequency: 125KHZ (ID card), 13 56MHZ (IC card) Sensing distance: 2-10cm Temperature range: -40℃-55 ℃ Applicable scope: parking, attendance, elevators, community management, etc Specification:A:5577:3xCUID+3xID Colour:Blue Material:plastic Package Contents: 1 x Access Card Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.