Sealable drain pipe coupling

A drain pipe coupling to sealably couple an insert pipe with an existing drain pipe, said drain pipe coupling comprising:

• a) an elastic tubular body concentrically positioned over said insert pipe and said existing drain pipe and having an internal diameter appropriately sized and contoured to grip and seal said insert pipe and said existing drain pipe;
• b) a first and a second retaining rings having a toroid body which is connected to a tightening tool from one end and is engaged with said tightening tool from other end through a railing tool, wherein said first and said second retaining rings are positioned at a distal end and a proximal end of said elastic tubular body to couple said insert pipe and said existing drain pipe,
• c) said tightening tool comprises of,
• i) a housing to house a cuboid body;
• ii) said cuboid body has an angled plane and wherein said cuboid body secured in said housing with a screw and a holder pin;
• iii) said railing tool engages and navigates other end of said retaining ring and places at a back portion of said housing;
• iv) a forcing part engages with said screw inside said cuboid body, and wherein said forcing part moves up and down by turning said screw, and
• v) a hook connected to said toroid body in an approximate distance to said cuboid body and is placed on said angled plane,
• whereby by turning said screw, said forcing part moves up and down and forces said angled plane of said cuboid body to said hook and causes an increase or decrease of diameter of said retaining ring, and whereby increase of diameter of said retaining ring deforming the distal and proximal end of said elastic tubular body to sealably contact with inner surfaces of said insert pipe and said existing drain pipe.