Abstract: A flexible endoscopic instrument for insertion through the lumen of an endoscope, comprises: a flexible cable; an actuating handle connected to a proximal end of the flexible cable; a tool assembly connected to a distal end of the flexible cable; a sheath that covers substantially an entire length of the flexible cable; and a tactile indicator portion formed along an outer surface of the sheath so as to be tactilely detectable by a user. The tactile indicator portion is formed at a predetermined distance from the distal end of the flexible cable so as to be tactilely detectable by the user at a position before the tactile indicator portion is inserted into a proximal end of the lumen of the endoscope and before the tool assembly exits a distal end of the lumen. When the flexible cable of the instrument is inserted into the endoscope, the user is pushing the instrument into the lumen of the endoscope, whereby he/she is physically touching the surface of the flexible cable's sheath.