A device, a method of making a device and a method of inserting a device into a tubular path. The device includes a tubular sheath with one or more helical slots formed therein and a control element that fits within the sheath. In one form, the device is an endoluminal device that simultaneously improves flexibility and structural rigidity though variations in one or both of slot shape along the length of the slot and slot pitch along the length of the tubular sheath. When the operator pulls at the proximal end of the control element while holding the outer sheath in place, the slots will tend to close in a preferential manner such that more precise control of device length and bending is enabled, while simultaneously providing improvements in structural rigidity during device insertion and navigation through a body lumen or related tubular member where tortuous paths may be encountered along the member path.