EZELAP Diamond Products EZE-FOLD Sharpeners EZE-FOLD models have a carring case that unfolds into a handle. When closed the case protects the diamond surface. When open the case becomes a functional handle. Flat Models Feature a 3/4" x 4" Diamond Stone   Model Description 500 Super Fine Grit (1200) - blue handle 501 Fine Grit (600) - red handle 502 Medium Grit (400) - purple handle 503 Coarse Grit (250) - black handle 504 Extra Coarse (150) - green handle   Double Sided Flat Models Feature a 3/4" x 4" Diamond Stone   Model Description 510 Super Fine Grit (1200)/Medium Grit (400)   2 Stone Set - silver handle   520 Fine Grit (600)/Coarse Grit (250)   2 Stone Set - gold handle Model 551 3-1/2" Diamond Coated Shaft 551 3-1/2" Diamond Round Shaft with small and large grooves for fishhooks   Model 571 Tapered Shaft for Sharpening Serrated Blades 571 Tapered Shaft for sharpening serrated blades   590 4" x 3/4" x 1/4" Oval Shaft, blue handle. Diamond grit: Super fine (1200)   591 4" x 3/4" x 1/4" Oval Shaft, red handle.Diamond grit: Fine (600) 591K 4" x 3/4" x 1/4" Oval Shaft, red handle.   Comes with Sports Knife