Series 6200 Medium Duty Service Doors. Loading dock and material handling locations demand a street-tough rolling service door that represents an exceptional value at a moderate price. The Model 6241 utilizes aggressive, yet innovative design, approaches to deliver sensible, high performance features that meet these demands. Series 6000 Service and Insulated Doors. The Series 6000 simplifies the process of selection by integrating the highest design principles into standard features. Simply stated, Series 6000 Service Doors are manufactured to meet your highest expectations of quality, fit and function with no excuses