The Oberheim 2 voice was the first Polyphonic Synth designed for musicians. It first appeared in 1974. It had no memory and was quiet a limited Synth.
In a reddit AMA on March 31st, 2015, Liam Howlett was asked, "Hi Master, is there any synth/gear you are addicted in?", to which he replied, "i rock analogue keyboards ,, oberheim 2 voice , arp 2600"
Liam pictured with his Oberheim Two Voice at BBC Radio 1 studios.
This is Oberheim Two Voice in Liam's studio during Invader's Must Die album recodings. That Puma whistle on it was a prize on online auction or something.
In these pictures from The Prodigy's Instagram you can see that Liam has this baby in use in his studio setup.