Zephyr 77 produced and distributed by the airgun centre Essex. French walnut stock. PTFE coated piston and spring. Including scope weight is about 11 lbs. Theoben designed the zephyr piston configuration. To keep friction co-efficient the walls of the piston head are concave, giving two narrow edges of contact against the cylinder walls. The piston seal has channels cut across it's surface which feed the vestiage of compressed air to the transfer port. Theoben also produce a lovely silencer on these to complete the whole package. Produced around 1986 but not sure on numbers. A HW80 Zephyr was also produced but are hen's teeth. Mach 1.5