Depending on the age and size of the student, an assortment of violin sizes are available as follows:
1/16 size,  1\10 size,  1/8 size,  1/4 size, 1/2 size, 3/4 size, 4/4 full size

Fine tuners on the tail piece near the violin bridge as shown in the
photograph are a good idea.  Tuning the violin is made a lot easier.