operated, lowering the top required unlatching two header catches, power lowering the top, exiting the car (or reaching over to the right side latch), and folding down the rigid section manually. Mazda introduced with the convertible the first integral windblocker, a rigid panel that folded up from behind the passenger seats to block unwanted drafts from reaching the passengers—thereby extending the driving season for the car with the top retracted. The convertible also featured optional headrest mounted audio speakers and a folding leather snap-fastened tonneau cover. The convertible assembly was precisely engineered and manufactured, and dropped into the ready body assembly as a complete unit—a first in convertible production. Production ceased in 1991 after Mazda marketed a limited run of 500 examples for 1992 for the domestic market only. In markets outside the US, only the turbocharged version of the convertible was available. North America The Series 4 (produced for the 1986 through the 1988 model years) was available with a naturally aspirated, fuel injected 13B-VDEI producing in North American spec. An optional turbocharged model, known as the Turbo II in the American market, was rated at and of torque at 3,500 rpm. The turbo model was introduced at the Chicago Auto Show in February 1986, with a target of 20 percent of overall RX-7 sales. The Series 5 (1989–1992) featured updated styling and better engine management, as well as lighter rotors and a higher compression ratio 9.7:1 for the naturally aspirated model, and 9.0:1 for the turbo model. The naturally aspirated Series 5's 13B-DEI engine was rated at , while the Series 5 Turbo was rated at at 6,500 rpm and of torque at 3,500 rpm. Mazda sold 86,000 RX-7s in the US alone in 1986, its first model year, with sales peaking in 1988. 10th Anniversary RX-7 Mazda introduced the 10th Anniversary RX-7 in 1988 as a limited production model based on the RX-7 Turbo II. Production was limited to 1,500 units. The 10th Anniversary RX-7 features a Crystal White (paint code UC) monochromatic paint scheme with matching white body side mouldings, tail light housings, mirrors and 16-inch alloy seven-spoke wheels. There were two "series" of 10th Anniversary models, with essentially a VIN-split running production change between the two. The most notable difference between the series can be found on the exterior- the earlier "Series I" cars had a black "Mazda" logo decal on the front bumper cover,