Scubapro introduced the stabilizer jacket in 1971, with a patented "360° flow through design", which allowed air to flow over the shoulders and under the arms, and around the cylinder mount. Later products from competitors avoided patent infringement by eliminating some of the air path options, such as separating the bladder under the arms or over the shoulders. These modifications also simplified the structure of the bladder. One of these later models was the Seatec Manta, with shoulder buckles and a softpac structure (without a rigid backpack)