Hi, all,
"Covers by Jill" was very convenient in the older days of purchasing through the state of California, because they gave preference in buying to women, vets and small businesses. Dennis Haley and Jill moved later, and at some point changed the name to Instrument Covers, same quality, same decent turnaround. I also purchased many leg wraps for stage pianos but I don't know about string covers. Not last I knew. You can get many varieties of cover materials; for concert pianos I've always gotten I think "Destiny Canvas", padded and quilted. I've also had her make smaller vinyl covers for lobby pianos and so on. I have sent her several patterns for odd or off-brand pianos and custom leg wraps.
Guy Michaels is their daughter, they've retired now, and she has all their patterns, logos, and methods. I knew her when she lived locally for a while, then she moved her business to Salem, Oregon. I've always called Guye directly (pronounced "ghee" like the French version of the male name Guy") at 971-388-7806,
By knowing her and calling directly, I never looked her up online, I don't see a website for her. But she's on Twitter, and if you find her there, you can see her operation. The business is now called Instrument Covers II.
Between the Haleys and Guye, that's the only place I have ordered covers for about 30 years. I've always been pleased, and their covers are on concert pianos in all the venues where I work. They last very well.
Good luck.
Kathy