A needle assembly comprising: a housing comprising a wall having an interior wall surface defining a cavity having a tip protector disposed therein; a needle which has a shaft, a needle tip and a non-uniform section; the needle passing through the housing and the tip protector; the tip protector comprising a proximal wall with an opening, the needle passing through said opening, an arm extending distally of the proximal wall; said arm further comprising a distal wall with an end section or finger for blocking the needle tip; a first and a second edge; a deflector plate being configured to deflect and move relative to the first and second edge, the deflector plate comprising a projection projecting into a cavity; wherein the non-uniform section on the needle has a larger cross-sectional dimension than the opening and is configured to engage the opening on the proximal wall in a used position; wherein the non-uniform section is a crimp, a material build-up, a bend or combinations thereof; wherein the housing is a catheter hub, wherein the tip protector further comprises a second arm that extends distally of the proximal wall and that is configured to stabilize the tip protector within the catheter hub; and wherein the second arm is opposite the deflector plate; characterized in that in a ready to use position of the tip protector, said arm is biased radially outwardly towards said second arm, said end section or finger of said arm is in contact with a side of the needle, and said arm is flexed, at least in part, about a point at the proximal wall when in abutting contact with the side of the needle, the end section or finger of said arm overlaps a portion of the needle in the used position, and wherein said deflector plate and said second arm are both biased against the interior wall surface of the catheter hub such that the tip protector is removably secured to the catheter hub. a housing comprising a wall having an interior wall surface defining a cavity having a tip protector disposed therein; a needle which has a shaft, a needle tip and a non-uniform section; the needle passing through the housing and the tip protector; the tip protector comprising a proximal wall with an opening, the needle passing through said opening, an arm extending distally of the proximal wall; said arm further comprising a distal wall with an end section or finger for blocking the needle tip; a first and a second edge; a deflector plate being configured to deflect and move relative to the first and second edge, the deflector plate comprising a projection projecting into a cavity; wherein the non-uniform section on the needle has a larger cross-sectional dimension than the opening and is configured to engage the opening on the proximal wall in a used position; wherein the non-uniform section is a crimp, a material build-up, a bend or combinations thereof; wherein the housing is a catheter hub, wherein the tip protector further comprises a second arm that extends distally of the proximal wall and that is configured to stabilize the tip protector within the catheter hub; and wherein the second arm is opposite the deflector plate; characterized in that in a ready to use position of the tip protector, said arm is biased radially outwardly towards said second arm, said end section or finger of said arm is in contact with a side of the needle, and said arm is flexed, at least in part, about a point at the proximal wall when in abutting contact with the side of the needle, the end section or finger of said arm overlaps a portion of the needle in the used position, and wherein said deflector plate and said second arm are both biased against the interior wall surface of the catheter hub such that the tip protector is removably secured to the catheter hub.