Set of 4 Retractable precision knives with blade locking feature. 4 Retractable precision knives with Blade locking feature Can be opened & closed with one hand Blades include: #10, #10A, #11 & #15 The set of 4 retractable precision safety knives are fitted with blade locking feature and are easily opened & closed using one hand. The different blade profiles are ideal for a variety of delicate cutting and trimming tasks. The profiles includes are colour coded as follows: Green #10, Grey #10A, Yellow #11, Red #15. The handles also includes a handy measuring scale.