Abstract: A flexible, non-porous tube characterized by the fact that the void spaces present in the luminal surface of a substrate tube of porous polytetrafluoroethylene are filled with a silicone or fluorosilicone rubber, that a continuous coating of said silicone or fluorosilicone rubber is not present on the inner surface of said tube, and that the inner surface of said tube incorporates surfaces of both the polytetrafluoroethylene and the silicone or fluorosilicone rubber. The tube has excellent lubricity, resistance to contamination, resistance to chemicals, and has exceptional tube flexing properties. The flexible tube may be employed, for example, as a tube for removal of gas destructively tested by a gas sensor, as a tube for transporting various liquids, and particularly as a tube in medical applications, such as a forceps channel tube, an endoscope channel tube, a bodily fluid transport tube, catheter tube, or the like. A method of making the tube is also described.

Abstract: A writing pen for heat developing photoconductive material including a pen having a nib formed of material of high thermal conductivity and pervious to light, for contacting photosensitive heat developing material. The pen has a light source for illuminating the photosensitive material through the pen nib contacting the material, and a heater embedded in the nib for heating the nib portion in contact with photosensitive material. The pen nib may include a light-pervious rotatable ball tip seated in a light-pervious ball receptacle.