The Shimano Deore XT/SLX 1x11 Upgrade Kit is perfect for upgrading an MTB purchased post-2013.

With quality MTBs in short supply (and very expensive) installing a 1x upgrade kit is a great way to refresh the bike and get back on the trails.  

Upgrade kit includes:

SL-M7000-11-R

SLX - RAPIDFIRE PLUS - Right Shift Lever - Clamp Band - 11-speed

11-speed SLX's SL-M7000 shift lever delivers crisp and reliable shifting for diverse mountain biking riding styles. The RAPIDFIRE PLUS lever features a long lever body and wider operating surface for consistent and secure shifting.

RD-M8000-SGS

SHIMANO DEORE XT - Rear Derailleur - Long Cage - SHIMANO SHADOW RD+ - 11-speed

Perfectly suited to a wide variety of MTB applications, the SHIMANO DEORE XT M8000 derailleur deliver race-worthy performance without breaking the bank.

CS-M8000

SHIMANO DEORE XT - 11-Speed - HYPERGLIDE - MTB Cassette Sprocket

The SHIMANO DEORE XT cassette shaves weight while maintaining durability thanks to an alloy sprocket carrier. This DYNA-SYS11 cassette delivers precise shifting even in the most demanding mountain biking situations.

11-42 or 11-46

CN-HG701-11

SHIMANO STEPS E6000 - 11-Speed - Super Narrow - HYPERGLIDE - SIL-TEC -E-BIKE Chain

The HG701-11 chain is directional and features SIL-TEC treatment on the roller link plate and pin link plate for increased durability. It is compatible with 11-speed road, MTB, and E-BIKES thanks to its reinforced design.

Installation Notes:

Proper installation will require a compatible 1x chainring or crankset/BB.  Your local Mechanic will be able to recommend best solution for your MTB

Most Bikes sold after 2013 are likely to fit this without major work.  If your bike currently runs a 3x9 gear combination then it is very likely you will also need a new freehub (if available) or new rear wheel to fit the 11-speed cassette.  If you wish to keep costs low then a 1x10 groupset is compatible with more bikes.