Although I have no reservations about using cup 'n cone BBs, sealed cartridge bottom brackets are great for many reasons. They are easy to install and require no service for the life of the part. If this is what you are looking for the Shimano BB-UN26 is a great choice. Nothing fancy (or expensive), just a good quality sealed BB from a leading parts manufacturer. Does require a specialty tool like the Park Tool BBT22 to install and/or remove.
- assorted lengths
- English Thread: 24T
- Left hand threaded on drive side
Although the BB itself is maintenance free, it doesn't hurt to remove it periodically and apply some grease to the threads and body to prevent seizing to the frame.