They were powered by the Volvo D9A300 EM-EC01 engine (9,364cc), which meets the Euro III emission standards. Of the 200 units, 50 were fitted with 4-speed Voith D864.3 automatic transmission, while the rest were fitted with 6-speed ZF 6HP 592 Ecomat automatic transmission. SBS7321D later had its transmission changed to the newer 6-speed ZF EcoLife automatic transmission. The bodywork and interior fittings was the evolution from the prototype trial on a B10TL (SBS9889U) by PSV International and ComfortDelGro Engineering (CDGE). The bodywork of these 200 units were built and assembled locally by CDGE. A further derivation of this bodywork was later offered by MCV as the DD103.
Air-conditioning was supplied by Denso of Japan. These buses originally used plastic destination plates as a cost-saving measure. Advances in technology have since made LED-based signs cheaper, and by end of 2011 all units were fitted with EDS supplied by LECIP.