Drug delivery device

A drug delivery device comprising:

• a housing having a first opening;
• a drug storage device including a delivery member having an insertion end configured to extend at least partially through the first opening in the housing;
• a plunger;
• a drive mechanism activatable to drive the plunger in a distal direction to expel a drug from the drug storage container through the delivery member;
• and
• a needle guard moveably disposed adjacent to the first opening, the needle guard having an extended position wherein the needle guard extends at least partially through the first opening and a retracted position wherein the needle guard is positioned away from the extended position toward the housing,
• wherein the needle guard has a base surface having a second opening and configured to contact an injection site, wherein the insertion end is configured to extend through the second opening when the needle guard is in the retracted position, and wherein a surface area of the base surface is between about 200 mm2 and about 315 mm2.