Foredom MK10 Maintenance Kit Maintenance kit for all new 1/6 HP series: SR, SRM, SRB. Each maintenance kit contains: 1 replacement inner flex shaft, 1 pair of replacement motor brushes, a tube of flexible shaft lubricant and instructions. Regular maintenance of your flex shaft machine will ensure smooth, problem free operation and extended life. Inner shafts should be cleaned and lubricated on a regular basis.