The Zealite Replacement Fitbit Alta Band is almost exactly like the original band that comes with the Alta. It is constructed of a TPE and TPU composite material with stainless clips and clasp. I found this band to be slightly softer than the original band and therefor slightly easier to to fasten, not that it could be any harder than the original band. It is available in two sizes and multiple colors including black, white, purple, Red, Navy, and Teal. Overall I feel this band is slightly better than the original and highly recommend it if you are looking for a replacement.
This band can be found here if you are interested in purchasing it.