The Slack Adjuster is a device for automatic adjustment of the clearance between Brake Block and Wheal tread. Stone India made Slack Adjusters are double acting i.e. it can either increase or decrease the slack depending upon the requirement. Both DRV2 and DRV2A Slack Adjusters are manufactured as per SAB Sweden design in models DRV2-600, DRV2-450, DRV2-300 as well as DRV2A-600 and DRV2A-600 and DRV2A-450 for both Coach and Wagon application. In addition IRSA-600, IRSA-600J as well as IRSA-450 Slack Adjusters are also manufactured as per Indian Railway's standard design.