Summary

1000 screws, a random selection of "the most popular sizes"..

They are mostly larger screws for watch cases, spectacle frames etc, but there are also a few dozen tiny screws for watch movements.

to see 250 smaller screws for watch movements.

See an information article,

Will we have the size you want?

PLEASE do not send the measurements and ask us to look through the box and measure them. I did once try this, - I eventually calculated that it could take several hours to find an exact match (there are thousands of screw types - length, diameter, head type, thread pitch...)

There are 1000 screws, and they are common sizes, and there is a fair chance that you will find the one you want. ..but not guaranteed.

My best suggestion is: buy them, and if you don't find the screw you want this time, then maybe you'll find one for your next job.