Simpson 1/4" Drop-In Internally Threaded Anchor 303 Stainless DIA25SSDrop in anchors are internally threaded drop in expansion anchors for use in flush mount applications in solid base materials. Minimum thread engagement should be equal to the nominal diameter of the threaded insert Model No. DIA25SS Drop In Anchor Coating Material : Type 303 304 Stainless Steel Drill Bit Dia. (in.) : 3 8 Length (in.) : 1 Rod Dia. (in.) : 1 4 Thread Length (in.) : 3 8 TPI : 20 Component Material, Anchor Body : AISI 303. Meets chemical