The M980 Rapidfire Plus shifter look similar to their predecessor on the outside however, on the inside they have received a complete re-design. While most companies would have simply added one more index click to go from 9 to 10 speed, Shimano decided to completely revamp the internals to provide what they call Vivid Indexing while adding that extra gear.
The most notable change is the linear shifting action as you run through the gears. Virtually, the same amount of force is used to shift regardless of where you are in the shifting range. Vivid Index shifting takes less effort to shift while offering a more positive and crisp feel. One quick adjustment makes the front shifter comaptible with double or triple cranksets. Simply brilliant.
The one design feature that separates Rapidfire Plus from other trigger designs is the fact that the top lever shifts both ways to up shift - the rider can choose from a push-push action or push-pull depending on their hand and finger position on the bar at the time of shifting.
If you are using M980 brake levers, you have an option to use iSpec, which replaces the bar clamp to fit in to the brake lever clamp, effectively giving you one clamp for both brake and shifter. Either clamp slides back and forth and also pivots up and down on the bar to let you find the perfect ergonomics for hand shape and riding style.
One pair of shifters include Teflon coated shifter cables and housing, end caps and ferrules.