The primary crown is a tooth shaped "cap" that is placed over a damaged tooth to provide it protection, fully encases the visible portion of the tooth that is exposed above the gum line. Mechanic can match the shape clamp to adjust crown, crown scissors can fix type appropriately, without skilled at first suggestion on resin model above or plaster model to practice. Letter D is for 1st molar and E is for 2nd molar. One crown of each size. (total 48 crowns) Available Size: 48 Different Sizes Can Be Chose Sizes with Mm:Allowable error range：±0.3mm Notice: The meaning of the D is 1st molar The meaning of the E is 2nd molar The meaning of the U and L are upper and lower L and R are left side and right side The number is size of the crown Size: D-UL-2: 8.0mm×6.6mm D-UL-3: 8.4×7.1 D-UL-4: 8.7×7.5 D-UL-5: 8.9×7.7 D-UL-6: 9.4×7.9 D-UL-7: 9.9×8.4 D-UR-2: 7.8×6.6 D-UR-3: 8.4×7.1 D-UR-4: 8.8×7.4 D-UR-5: 9.1×7.4 D-UR-6: 9.5×7.8 D-UR-7: 10.1×8.4 D-LL-2: 7.5×6.3 D-LL-3: 8.0×6.8 D-LL-4: 8.4×7.0 D-LL-5: 8.7×7.3 D-LL-6: 9.2×7.7 D-LL-7: 9.7×8.3 D-LR-2: 7.6×6.3 D-LR-3: 8.0×6.7 D-LR-4: 8.3×7.0 D-LR-5: 8.6×7.5 D-LR-6: 9.2×7.8 D-LR-7: 9.7×8.2 E-UL-2: 10.0×9.0 E-UL-3: 10.7×9.5 E-UL-4: 11.2×9.9 E-UL-5: 11.6×10.3 E-UL-6: 12.0×10.8 E-UL-7: 12.3×11.1 E-UR-2: 10.0×8.9 E-UR-3: 10.6×9.6 E-UR-4: 11.0×9.9 E-UR-5: 11.5×10.4 E-UR-6: 11.9×10.6 E-UR-7: 12.2×11.0 E-LL-2: 9.7×8.9 E-LL-3: 10.1×9.1 E-LL-4: 10.3×9.4 E-LL-5: 11.0×9.9 E-LL-6: 11.4×10.2 E-LL-7: 11.8×10.5 E-LR-2: 9.5×8.7 E-LR-3: 10.1×9.1 E-LR-4: 10.3×9.5 E-LR-5: 10.8×9.9 E-LR-6： 11.2×10.2 E-LR-7： 11.6×10.5 Packaging contents:Kids Primary Molar Crowns 5/Pk All Sizes or KIT of 48 Pcs As Per Order Kit Contains 1 each of all 48 sizes