So about 3 weeks ago I installed the first pair of seals. Exchanged them for a second pair. NOTE: This is the result of resetting the hook to +100 degrees several times a day. They were also exposed to rain and cold. In general, they suffered a bit from being constantly on and off. The first pair would most likely be used for a full month, but for safety reasons I decided to replace them. However, they seem to last longer over long distances or in the hands of trucks and trailers that stay together all the time. Also for the price. I have the ability to change them as often as needed. (They cost about $5 compared to 2 seals at gas stations. For the price of 4 seals I got 36.) Overall good product, good price, would buy again.