Olfa Retactable Touch Knife Yellow TK-4. 

Touch knife. 

This pocket-sized, multi-purpose knife features a stainless steel blade, blade slide lock and hanging hole to easily slide onto your keychain. 

Can be used for a number of purposes, and easily fits in your pocket, purse, desk or glove compartment. 

Dimensions: Approximately 1 1/2 inch diameter.    

CHK-TK4Y