The S5.142 (AKA DST-25) is a liquid pressure-fed rocket engine burning N2O4/UDMH with an O/F of 1.85.
[5] It was used in KTDU-80 propulsion module from the Soyuz-TM to the Soyuz-TMA-M, as the low thrust thruster (DPO-M).
[3] As of the Soyuz MS, KTDU-80 does not use DPO-M anymore.
[6] The S5.142 generates 25 N (5.6 lbf) of thrust with a chamber pressure of 0.88 MPa (128 psi) and a nozzle expansion of 45 that enables it to achieve a specific impulse of 285 s (2.79 km/s).
[1][5] This engine has been used in crewed Russian space program since the Soyuz TM-23.