Dilator with slit and slidable sleeve

A dilator comprising:

• a tube having a first end, a second end, and a tube wall extending between the first end and the second end, wherein the tube wall comprises a cylindrical barrel and a tube wall longitudinal length, wherein the first end comprises a first end opening and the second end comprises a second end opening,
• a channel extending a length of the cylindrical barrel from the first end opening, through the cylindrical barrel, and to the second end opening,
• wherein the cylindrical barrel comprises a solid wall having a constant outer diameter and a tube slit extending entirely through the solid wall, longitudinally, from the first end opening to the second end opening, opposite of the first end opening;
• an elastic, unitary sleeve, slidable longitudinally and transversely to the cylindrical barrel when disposed on the tube, comprising
• at least one sleeve opening,
• a sleeve wall having a sleeve wall longitudinal length that is less than the tube wall longitudinal length,
• a sleeve slit extending longitudinally entirely through a wall thickness of the sleeve wall, wherein the sleeve slit is selectively mis-alignable with the tube slit to prevent removal of the dilator from a guide, an inner diameter of the sleeve wall forming a sleeve channel, and wherein the elastic, unitary sleeve is removably disposed on the tube by inserting the tube inside the sleeve channel thereby elastically stretching the elastic, unitary sleeve;
• and
• wherein the tube slit is closed by the elastic, unitary sleeve during dilation.