them to fail in the event of a predetermined electrical signal from the circuitry 125 one example of a kevlar fuse type device is shown and described in u s pat no 5 558 153 and that patent is incorporated by reference in its entirety herein fig5 is a cross section view showing the valve 302 in an open position as shown the retaining members 310 have been caused to fail and the plunger 305 has been moved from a first closed position fig4 in which port 257 is blocked by the plunger 305 to an second open position fig5 wherein fluid traveling in port 257 is free to enter and pass through the valve due to the extended spring 306 which was initially held in a compressed position fig6 and 7 are section views of the valve assembly 300 from a different rotational position shown in the open and closed positions respectively visible in each is the valve 302 with its plunger 305 biased by the spring 306 in fig6 the port 257 not shown leading into the valve is blocked by a plunger member 307 in fig7 however port 257 is visible and the fluid therein is in communication with the fourth fluid path 258 leading out of the valve fig8 is a cross section view showing a lower portion of the tool 100 including ball seat 200 with ball 201 held therein the ball seat is constructed of a plurality of castellations 202 equally spaced around a perimeter of a sealing ring 205 and more completely illustrated in fig9 a d which include various perspective views of the ball seat 200 each castellation 202 has an angled inner surface 203 and is mounted at a lower end to a sealing ring 205 the ring 205 includes.