They are 8 ohm so they work with Loksound 4, Zimo or Hornby TTS sound decoders.
49x17x8mm Compact Bass Reflex DCC Sound Speaker With HM7000 Plug (8 ohm)
DCCS01-04 DCC Supplies OO 4 OHM Bass Reflex Speaker - Pack of 4 (Pre-Owned)
ESU 50343 DCC Speaker 29 x 65 x 14mm 4 Ohm Bass Reflex
100x45x20mm O Gauge Bass Reflex DCC Sound Speaker (8 ohm)
ESU Loksound 50348 Speaker, 18mm x 35mm x 11mm, 4 Ohms, Bass Reflex
ESU Loksound 50343 Speaker, 29mm x 65mm x 14mm, 4 Ohms, Bass Reflex