spirit and scope of the invention for example a safety rod could be added for an even higher measure of safety thus if both springs 12 and 16 were to fail the rod would hold the fixtures together the rod could be attached using keyholes from the rod into the fixtures another example used in the application of securing the outer end mounts 18 could be the use of flanges these flanges could take the place of the shoulder of the inner end mount flanges could be machined directly onto the fixtures 20 and 21 or arm of the fixture 20 and 21 depending on the application these flanges would then hold the outer end mount 18 in place also depending on the fixture 20 and 21 differing sizes of outer end mounts 18 and keyholes may be used in relation to the springs 12 and 16 differing sizes and materials may be used depending on the strength need and the function of the device free length pitch diameter coil diameter and the number of coils may all vary similarly the diameter of the outer end mounts 18 may vary depending on the outer spring 16 coil diameter and the size of the fixtures 20 and 21 attached fig7 illustrates an end mount 50 according to embodiments of the present disclosure in which a coating 40 has been applied to certain surfaces of the end mount 50 the end mount 50 is generally similar to other end mounts disclosed herein the grooves of the end mount 50 come.