Dear Margaret,

I think the correct (& not phonetic) transcription, done in hideous "extended
Wylie" would
be:

oM su pra tiSh+Tha badz+ra ye swA hA

Or in 'ordinary wylie' (but for typographic reasons, with dotted Sanskritic
consonants
having their dots placed immediately before them):

o.m su pra ti.sh.tha badzra ye swâ hâ

(I assume the letter tha ought to be reversed, even if it isn't in your
example.)

This is not a mantra 'of' any particular deity. It's the most general mantra
for performing
consecrations (in Sanskrit prati.s.thâ). It is the high point of the ritual.
In short-form
consecrations it may be practically the only thing there is, besides the flower
throwing (in
form of barley or rice 'flowers').

See Yael Bentor, Consecration of Images and Stûpas in Indo-Tibetan Tantric
Buddhism, E.J.
Brill (Leiden 1996), page 320. (It is available in major research collections
in every
country; given the price it is hard to suggest buying it.)

I imagine you would have found this mantra on the back of a thangka painting or
something similar. You do very often find it on artworks, sometimes alone, but
usually as
part of a group of mantras.

Yours,
Dan Y.