Within a technical specification you should avoid reference which may favour or eliminate suppliers e.g. by asking for a specific material or goods.
You should not reference a specific make or source or to a particular process, trademark, patent, type, origin or means of production.
Do not specify "Hoover" when you mean a vacuum cleaner or "Intel" when you mean a central processing unit of a personal computer.
In exceptional circumstances such mention may be justified if:
In either of the above circumstances such mentions should be accompanied by the words "or equivalent".