Download the ZTBF921.6J-TF datasheet PDF.
This datasheet also covers the ZTBF455E-TF variant, as both devices belong to the same ceramic resonator family and are provided as variant models within a single manufacturer datasheet.
Note: The manufacturer provides a single datasheet file (ZTBF455E-TF-ChequersElectronic.pdf) that lists specifications for multiple related part numbers.