These restrainers are made from Perspex cylinders mounted on a flat black Perspex base. All the models have free access through both extremes, by opening the respective tilting door that is fixed by a screw at the upper part of the restrainer. A hole at the base of the door allows for the whole tail to be available for tail injections/ sampling, pulse transducer etc. The lateral holes and slots allow for good ventilation and access to the animal. The mouse model has a black nosecone for a less stressful environment and entry, and also access in the top of the restrainer. The available space for the animal can easily be adjusted by sliding the doors and fixating with the upper screws.