Shimano RD-L541 is a rear derailleur designed for use with Shimano Index System (SIS). It is compatible with 6-speed freewheels and can accommodate a wide range of gear ratios. The derailleur features a top adjustment bolt for fine-tuning the position of the guide pulley in relation to the top gear, and a low adjustment bolt for adjusting the position of the guide pulley in relation to the low gear. The derailleur also has a B-tension adjustment bolt, which can be used to adjust the distance between the guide pulley and the low gear.