-in-1 detection lens keychain is a versatile tool for detecting marked game cards and mahjong tiles. With its white, blue, green, and purple lights detection, you can easily spot invisible ink markings. To use, simply select the appropriate light and scan the cards or tiles. This compact and portable device ensures you can maintain game integrity wherever you go. 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 -Multiuse solution: detection lens keychain that can identify white, blue, green, and purple lights, suitable for multiple needs -High accuracy: detection lens ensures precise and reliable light inspection, crucial for both professional and personal use -Portable and convenient: keychain design makes it easy to carry, allowing for immediate light detection whenever necessary -Broad applicability: suitable for optical shops, laboratories, and personal use, providing a versatile tool for different settings -Durable design: constructed to be durable and resistant to damage, ensuring it remains effective and reliable over time Package list: 1 x lens 1 x pouch