DuPont StoneTech and Miracle Sealer are good sealers for travertine tile. Travertine is a limestone tile, and it is porous and subject to staining from spilled liquids. Sealers and liquids with acids tend to etch the tile, so a water-based or alkaline sealer is best.
To provide protection against staining, a surface protector sealer is best. This type of sealer prevents liquids from seeping into pores and staining the stone but may alter its finish if it has a tint added to it. Travertine usually ships with a wax coating that must be removed before sealing. Sealing can be applied by rubbing small areas of the sealant into the tile with a rag. Multiple coats can be applied after drying. Excess sealant should be wiped off immediately to prevent streaking, and the tile can be buffed with a microfiber or cotton cloth when complete.