Some interesting classifications

B26B21/00 - Razors Of The Open Or Knife Type; Safety Razors Or Other Shaving Implements Of The Planing Type; Hair-Trimming Devices Involving A Razor-Blade; Equipment Therefor
B26B21/02 - Involving Unchangeable Blades
B26B21/04 - Razors Of The Knife Type
B26B21/06 - Safety Razors With Fixed Blade, E.g. With Moulded-In Blade
B26B21/08 - Involving Changeable Blades
B26B21/10 - Safety Razors With One Or More Blades Arranged Longitudinally To The Handle
B26B21/12 - Combined With Combs Or Other Means For Hair Trimming
B26B21/14 - Safety Razors With One Or More Blades Arranged Transversely To The Handle
B26B21/16 - Involving Blades With Only One Cutting Edge
B26B21/18 - Involving Blades With Two Cutting Edges
B26B21/20 - Involving Blades With More Than Two Cutting Edges; Involving Disc Blades
B26B21/22 - Involving Several Blades To Be Used Simultaneously
B26B21/24 - Of The Magazine Type; Of The Injector Type
B26B21/26 - Of The Continuous Ribbon Type
B26B21/28 - Of The Drawing Cut Type, I.e. With The Cutting Edge Of The Blade Arranged Obliquely To The Handle
B26B21/30 - Of The Type Carrying Pivotally-Mounted Caps
B26B21/32 - In Razors Involving Double-Edged Blades
B26B21/34 - Of The Type Carrying Rollers
B26B21/36 - With Provision For Reciprocating The Blade
B26B21/38 - With Provision For Reciprocating The Blade By Means Other Than Rollers
B26B21/40 - Details Or Accessories
B26B21/42 - For Cutting Hair Of Preselected Or Variable Length
B26B21/44 - Means Integral With, Or Attached To, The Razor For Storing Shaving-Cream, Styptic, Or The Like
B26B21/46 - For Illuminating The Skin
B26B21/48 - Heating Means
B26B21/50 - Means Integral With, Or Attached To, The Razor For Stropping The Blade
B26B21/52 - Handles, E.g. Tiltable, Flexible
B26B21/54 - Razor-Blades
B26B21/56 - Characterised By The Shape
B26B21/58 - Characterised By The Material
B26B21/60 - By The Coating Material