The Altus RD-M310 is a 7/8-speed MTB rear derailleur. It has a low profile with Shimano's double servo-pantograph technology, which improves adjustability and makes the rear derailleur more resistant to weather conditions and dirt. Another advantage is that the rear derailleur is always a short distance above the respective sprocket, thus ensuring smooth, easy and gentle shifting. In addition, the wider link ensures high durability and precise shifting.