Ensure in your card games and mahjong sessions with -in-1 detection lens keychain. This handy tool features white, blue, green, and purple lights to detect invisible ink markings on cards and tiles. To use, choose the light that matches the ink type and shine it on the surface to reveal any hidden marks, making it an essential accessory for any serious gamer. Features -Color:Assorted Color -Material:Acrylic, artificial leather -Size:19.70X1.80X0.60cm/7.74X0.71X0.24in -Size:13.80X3.30X0.50cm/5.42X1.30X0.20in -Light detection: lens keychain capable of detecting white, blue, green, and purple lights, addressing various detection needs -Precision and reliability: detection lens offers high accuracy, ensuring dependable light inspection results -Portable keychain: lightweight and easy to carry, the keychain design allows for convenient light detection on the move -Versatile applications: ideal for use in optical shops, labs, and personal settings, making it a flexible tool for different environments -Durable and sturdy: designed to be durable and resistant to damage, ensuring performance and reliability Package list: 1 x lens 1 x pouch