Police believe three burglaries in the Shotton area are linked.
Detectives are investigating the incidents and are urging people to come forward with information.
All three burglaries happened between 11.30pm on Friday, October 13, and 7am on Saturday, October 14, at units on Thornley Station Industrial Estate, Shotton Colliery.
The first unit targeted had a black Citroen Berlingo van along with various tools and a bench stolen, after raiders forced entry into the building causing a large amount of damage.
At the second unit, large quantities of clothing were taken including school uniforms belonging to various local schools and academies, Peterlee Ladies Running Club and Wingate Striders trainers and hoodies, as well as a number of Hi-Tec and Grafters shoes.
The last unit to be broken into lost more than £500 worth of copper and a Hitachi DV20VB2 impact drill.
PC Craig Lambton, from Durham Constabulary, said: “A number of businesses have been targeted and various items have been stolen that are so valuable to the companies. I would urge anyone with any information or anyone who knows of the whereabouts of the property to come forward.”
Contact police with any information on 101, quoting incident number 133,191 and 95 of October 14.
Alternatively information can be passed to Crimestoppers anonymously on 0800 555 111.