Additional teats for Wee Go glass bottles can also be bought separately:

Stage 1 teat, 0-3 months (retail pack of 2) - as shown in picture.
Stage 2 teat, 3-6 months (retail pack of 2)
Stage 3 teat, 6 months+ (retail pack of 2)
Y-cut teat, fast flow (retail pack of 2)