How durable is the printing on these labels. I plan to use them on musical instrument cases.

The Weatherproof Vinyl for Laser is a very durable material but to ensure that the toner is properly fused, we would recommend running a test print with the default printer settings. If you see that the toner is smudging or flaking off, adjust the material type setting to a heavier option like Labels or Cardstock. This will slow down the print feed, applying additional heat to the toner for proper fusion. You are welcome to visit the link below to request free samples of this material for testing. https://www.onlinelabels.com/samples

Are these removable? Will they adhere to glassware?

The Weatherproof Vinyl for Laser is a very durable material with a permanent adhesive so it is not considered to be removable. It works well on a variety of surfaces, especially industrial applications, and should adhere to glassware as well. If you'd like to try samples of these or any of our other materials, please visit the link below to complete our sample request form. https://www.onlinelabels.com/samples

Do these labels only come in white?

Yes, at this time our Weatherproof Vinyl Laser (LV) is only available in white. We do offer a few other weatherproof options at the link below for laser printers. This includes the Weatherproof Silver Polyester Laser (SP), as well as the Clear Gloss (CL) and Clear Matte (CX) Laser. https://www.onlinelabels.com/materials/weatherproof-labels