A needle, catheter, and housing assembly is provided. The assembly includes a slider portion that slides relative to the housing. The slider portion can be actuated by a caregiver/operator such that a catheter can be threaded into a patient with simple movement of the operators thumb or other finger. The assembly also includes an improved flash chamber. The flash chamber utilizes capillary action and/or a visible portal area to provide a caregiver/operator with more immediate information as to whether the needle has been inserted in the vein or artery.
