<Tr> <Td> No. 25 </Td> <Td> </Td> <Td> 4, 4 Graduated, 4 Long, 6 </Td> <Td> A front - facing straight blade with flat back (similar to #15a) </Td> <Td> </Td> </Tr> <Tr> <Td> No. 25a </Td> <Td> </Td> <Td> 4, 4 Graduated, 4 Long, 6 </Td> <Td> A triangular straight blade with flat back edge taking a downwards angle (similar to #10a, shorter than #26) </Td> <Td> </Td> </Tr> <Tr> <Td> No. 26 </Td> <Td> </Td> <Td> 4, 4 Graduated, 4 Long, 6 </Td> <Td> A triangular straight blade with flat back edge taking a downwards angle (similar to the #15a, longer than #25a) </Td> <Td> </Td> </Tr> <Tr> <Td> No. 27 </Td> <Td> </Td> <Td> 4, 4 Graduated, 4 Long, 6 </Td> <Td> </Td> </Tr>

A #12 knife blade on a #7 handle is most commonly used for what type of surgery