Thomson elite x4 mtb stemx4 is absolutely the best combination of strength and weight available enduro and downhill riders can run thomson confidently yet x4 is light enough for cross country and cyclocross x4 offers precise steering and tracking for the ultimate in control while riding too many modern mountain bike stems sacrifice strength and torsional stiffness for a few grams of saved weight the thomson x4 is the leader in strength and stiffness the thomson x4 stem allows you to realize