A housing may have a needle, plunger, and bias mechanism supported within the housing by a tab configured to retain the plunger in position and to allow the plunger to move under bias force imparted by the bias mechanism to move the needle to an insert position when the tab is removed. A base and a structure may be configured for relative movement there between and may be adapted to be secured to a user with a cannula extending through a body of the structure into the user during use of a medical device. A housing may be adapted to be secured to a user to support a medical device operable with an insertion needle, the housing having a magnifying material for increasing visibility of an injection site.