In the era where air-conditioned buses were still considered a luxury of choice, Trans Island Bus Services (TIBS) made a purchase for 73 non air-conditioned O405 units. These units bear the same supercharged Mercedes Benz OM447hA engine (11,967cc) and the 4-speed ZF4HP500 automatic transmission, but they have been fitted with sliding windows, vents on the top of the exterior windows, leather-covered seats, and the Hanover Displays flip-dot EDS. These non-airconditioned Euro I buses were bodied by Hispano Carrocera and introduced in 1995.

When the policy of air-conditioned buses was changed in the turn of the century to make them as standard, TIBS proceeded to install Hispacold or Denso air-conditioning in all units by 2001. Up to 2012 very little change has been made to the interior and exterior of these buses, save for replacement of seat covers and a few EDS units. They can be found in a wide range of services, though not as wide as what the original air-conditioned O405s enjoy.

A new round of refurbishment from July 2012, to extend the lifespan of these buses for 2 more years, resulted in the removal of the distinctive sliding windows and the respraying of its interior with a new colour scheme. The last remaining units were withdrawn from service in January 2015, thus marking an end to the era of converted air-con public buses that were once common on the roads of Singapore.