Methods and apparatus to apply axial force to a packer in a downhole tool are described. A metal layer including tungsten is formed to fill the first contact hole. The rear surface extends upwardly from the bottom surface. A WCD can receive the downlink resource block, recover the encoded data from the OFDM symbols, and use the one or more orthogonal codes assigned to it to recover the data for that WCD from the encoded data. A control clutch 33 controllably couples the propshaft 19 to an input shaft 32 which drives a final drive bevel pinion 31 which meshes with a crownwheel 27 fast with the large diameter spur gear 66. Other features can include an internal frame, a pivotal attachment between the lower seat and seatback and the support arch can be made of tube steel and have padding.