Shaviv B Blade Holder 153-29000 by Vargus. All blades marked with prefix "B" will fit into this holder. To insert or to release blades, press the sleeve in the direction of arrow. Blades B-10, B-25, B-20, B-30, B-40, B-50C, B-60 & B-70 can be inserted vertically or horizontally.