Answer by taking a quote from the following article:

Graeme Obree (born 11 September 1965), nicknamed The Flying Scotsman, is a Scottish racing cyclist who twice broke the world hour record, in July 1993 and April 1994, and was the individual pursuit world champion in 1993 and 1995. He was known for his unusual riding positions and for the Old Faithful bicycle he built which included parts from a washing machine. He joined a professional team in France but was fired before his first race. Obree has created some radical innovations in bicycle design and cycling position but has had problems with the cycling authorities banning the riding positions his designs required.

Obree had built frames for his bike shop and made another for his record attempt. Instead of traditional dropped handlebars it had straight bars like those of a mountain bike. He placed them closer to the saddle than usual and rode with the bars under his chest, his elbows bent and tucked into his sides like those of a skier. Watching a washing machine spin at 1,200rpm led him to take the bearings, which he assumed must be of superior quality, and fit them to his bike. Obree later regretted admitting to the bearings experiment, because journalists referred to that before his achievements and other innovations.  Obree called his bike "Old Faithful". It has a narrow bottom bracket, around which the cranks revolve, to bring his legs closer together, as he thought this is the "natural" position. As shown in the film, he thought a tread of "one banana" would be ideal. The bike has no top tube, so that his knees did not hit the frame. The chainstays are not horizontal to the ground. Thus the cranks can pass with a narrow bottom bracket. The fork had only one blade, carefully shaped to be as narrow as possible. A French writer who tried it said the narrow handlebars made it hard to accelerate the machine in a straight line but, once it was at speed, he could hold the bars and get into Obree's tucked style.  At a high enough speed, [I could] tuck in my arms. And, above all, get in a very forward position on the bike, on the peak of the saddle. The Obree position isn't advantageous simply aerodynamically, it also allows, by pushing the point of pedalling towards the rear, to benefit from greater pressure while remaining in the saddle. You soon get an impression of speed, all the greater because you've got practically nothing [deux fois rien] between your hands. Two other things I noticed after a few hundred metres: I certainly didn't have the impression of turning 53 x 13, and the Obree position is no obstruction to breathing. But I wasn't pedalling at 55kmh, 100 turns of the pedals a minute, yet my arms already hurt.

Does the bike have other custom features?
The bike has no top tube, so that his knees did not hit the frame. The chainstays are not horizontal to the ground.