Hi! I am switching to Lantus tonite for the 1st time. Got the Solostar pen & a friend gave me 100U needles with 1/2mL on the side. Are these correct? I didn't fill the rx I got the from vet & got the Solostar pen from a friend. Help! Thanks alot! These syringes have no 1/2 units listed on them or 1/4 either.