1DURABLE ALUMINUM ALLOY: The ring sizer mandrel is made of aluminum alloy. Lightweight, durable and portable 2SMOOTH SURFACE: 31 piece finger sizer kit is made of stainless steel. Fine workmanship bring smooth edges, will not hurt hands 3ACCURATE SIZE: Metal ring measure ruler is available in 4 sizes, including size 215(specific to quarter size), Hong Kong size(HK), Japan size, European size(CU). Finger size gauge is size 015(specific to half size) 4EASY MEASUREMENT: With this ring size measurement tool, you can quickly calculate the size of ring and finger. Then give your husband, wife, girlfriend, boyfriend a ring of the correct size as a surprise gift 5DOUBLE HEADED JEWELRY HAMMER: Used to hold and adjust rings. The clever design of the soft tip can well protect your precious jewelry from wear and tear