Copenhagen based, Simple bike, has launch a range of alternative washer/spacers to work with horizontal dropouts. The 'Wheel Slammers' come in width measurements from 1.5mm, for those who like to run wheels snug into the dropout, to 8mm for those who run their wheels close to the end of the dropout.
The idea behind the product, is to make chain tensioners redundant. Simply measure the space between your axle and the front of the dropout and fill it with a 'Slammer', which slots into the dropout and around the axle, effectively rendering the wheel unable to slide in the dropout
The brand, which also has new hubs, frames, linear brake cables, as well as several other smaller components, is available in the UK via IMG distribution.