I have had very satisfactory service from my MK3 and MK4 yaw strings.
Nice clear adhesive patch that can be removed from the canopy without leaving a mark. Very satisfying triangular shape to the adhesive patch gives me a very warm feeling inside whenever I examine it during flight.

Also, very excellent customer service. One time at Minden I was having some questions about the length and responsiveness of the fibrous indicating structure and the company representative drove up to my plane and addressed my concerns in less than one hour from the telephone call.