A drip irrigation emitter may be provided with a coupler for bonding to an inner surface of a conduit. The emitter may include for example a button flow restrictor. The coupler may optionally provide an outlet zone on the conduit surface that is large enough for automated perforation. Bonding the emitter to the surface of the conduit may have a minimal effect on the dimensions and/or properties of the conduit. A button drip irrigation emitter may optionally include a two part labyrinth. The labyrinth may for example be confined between a cylindrical surface and a cover and/or wind between intermeshing baffles on the cover and/or the surface.