A coupler for use in sealing a joint between two pipes. The coupler is comprised primarily of two center sections and two end caps. The two center sections are engagable with one another and the two end caps are engagable with the center sections. Gasket rings create seals between the two center sections as well as between the two center sections and the cap rings. The center sections are dimensioned to create a volume of space within the coupler, thus permitting the coupler to accommodate offset joints. The gasket rings between the cap rings and the center sections can be longitudinally spaced apart, minimizing the angular deflection of the coupler with respect to the pipes when the pipe joint is offset. The center sections and end caps can be lockably engaged.