It is 4.35V.

datasheet I found here: http://www.raytechpower.com/Downloads.asp?ID=21

7.1 Standard Charge
This "Standard Charge" means charging the cell with charge current
1475mA and constant voltage 4.35V at 25 ℃for 3hours.

7.2 Standard Discharge Capacity
The standard discharge capacity is the initial discharge capacity of the cell, which is
measured with discharge current of 590mA with 2.75V cut-off at 25 ℃within 1hour after the standard charge.
Standard Discharge Capacity ≥ 2850mAh