Police are appealing for anyone asked to buy a distinctive quad bike to get in touch.
Two have been stolen from CN Trading based at Sandbeds Yard on Halifax Road in Hebden Bridge.
They were taken some time between 8.30pm on Monday, June 6 and 7am on Tuesday, June 7.
One of the quads was made specifically for the company and is the only one that is yellow in all of Britain.
The other is a camouflaged green colour.
Anyone with information that could help with the police’s investigation or who thinks they may have been offered one of the quads for sale should call PC Kate Crowther on 0845 6060606.
Anyone with information can also call crime fighting charity CrimeStoppers, where information can be passed on anonymously, on 0800 555111.
For crime prevention advice visit www.westyorkshire.police.uk.