to the rear. Available across all lengths except the M990, the Slimline is identified by having an SL-suffix in the chassis code, e.g. M780SL for a long version. The Optare Solo Slimline is a 25-seated low-floor bus to replace the Optare MetroRider. The compact size of an M780SL, with its seating capacity of 25, has made it a popular choice for replacing earlier-generation minibuses, such as the MCW Metrorider, and other van-based buses. SE In June 2006, Optare announced the arrival of another Solo model – the Solo SE. At just in length, it is the shortest Solo offered, and is capable of seating 23. It also uses a single-piece entrance door as an option. This is a variant of the Slimline – hence it is wide, but noticeably the rear track has been reduced compared to previous Slimline models, eliminating the need for wheelarch extensions on the rear of the bus. Optare also plans to produce a long version of the SE. The first SE built, the former Optare demonstrator, entered service with Regal Busways, of Essex, in September 2006. The company has since acquired a further four examples. EV In March 2009, Optare launched the all-electric version of the Solo, the Solo EV. The vehicle's top speed is limited to . Since the summer of 2013, the vehicle uses a high-efficiency MAGTEC P180 Permanent Magnet Motor-Gearbox rated at 150kW and powered by two banks of Valence lithium-ion phosphate batteries. The two packs work in parallel and provide 307V with a total capacity of 92kWh. Solo+ In November 2008 the 'new' Optare unveiled the Solo+ – a completely restyled variant to celebrate ten years of the Solo as a new low-entry bus and was launched at the Euro Bus Expo 2008. It shared the same styling with the Rapta, which was launched at the same show. It sees the return of the flat side windows and roof as well as a steeper front end with an integral destination box. Proposed options include a full electric drive. However, the plan of producing the Solo+ was dropped afterwards. The new product met with a poor market response and never made it beyond the prototype stage. The further development required to make the product an improvement on previous models was possibly deemed to be too great (and costly), the plans being shelved. Solo SR In October 2007 Optare unveiled the Solo SR