To improve the lifespan of a rubber crawler by reducing as much as possible cracks due to bending at the time of wraparound. The vane end rails also include a number of vertical seal slots spaced along the axial direction to receive a number of vertical riffle seals. Each socket module is mechanically and adjustably engaged with at least one other socket module, whereby the device is expandable and compressible such that both small power plugs and larger AC adapters may be plugged into the electrical socket of each socket module.