a device , system and method are provided for using a seal sub to isolate a well . the seal sub generally has a primary channel extending through the seal sub and seat positioned within the primary channel . as a ball setting tool passes through the seal sub and the seat , a ball connected to the setting tool with a shear pin contacts the seat and selectively connects to the seal sub . a predetermined force can be applied to the ball setting tool to break the shear pin , which leaves the seal ball in place , and the seal sub and the seal ball isolate the downhole pressures and contents from the uphole pressures and contents .