This is one each of our L14811 achromatic objective lens, 51mm diameter by 360mm focal length, and our L14812 15mm wide field eyepiece. The combination makes a decent quality inexpensive telescope with 24 power. A great project for kids. Just add some cardboard or PVC tubing.
For the objective, place the crown (double convex) with its strongest curve against the negative side of the flint. Use a couple pieces of masking tape on the edges to hold them together. The crown side faces the sky or the object you plan to look at. Unused.