DVT prevention pumps, also known as Sequential Compression Devices (SCDs), are made by medical device companies like Medline (Hemo-Force), Compression Solutions (PlasmaFlow, SCDS), Kinex Medical, and Precision Medical Products (VenaPro). These manufacturers produce pneumatic devices with inflatable sleeves that massage the calves and legs to improve blood flow and prevent dangerous clots after surgery or for at-risk patients, often used at home. 

How They Work:
These pumps inflate and deflate sleeves around the legs in a sequential, bottom-to-top motion, mimicking walking to prevent blood from pooling and forming clots (Deep Vein Thrombosis). 

Where to Find Them:
You can find these devices through medical suppliers, directly from manufacturers, or via distributors specializing in home medical equipment (DME).