Endoscopic apparatus, including a probe ( 9 ) having an anterior component ( 12 ) and a posterior component ( 14 ), and a flexible dual-sleeved tube ( 31 ). The flexible dual-sleeved tube consists of a flexible external sleeve ( 26 ) and a flexible internal sleeve ( 36 ) within the external sleeve. The sleeves are coupled between the anterior component and the posterior component so as to define an enclosure ( 37 ) between the sleeves, which enclosure is inflated in order to propel the anterior component within a lumen ( 49 ).
