A probe 100 which can be formed from a molded plastic provides an inexpensive construction for a probe which may be readily replaced in electrical testing apparatus, particularly of the automated type. A conductive contact tip 18 is preferably co-molded into a cantilevered portion 14' of a body block 14 and a conductive material 16 is provided over a portion of the surface of the body block 14 extending from the contact tip 18 to an attachment portion 15 of the body block. Cooperating attachment structures 22, 24 are provided on both the body block 14 and a holder block 20 to provide a snap fit therebetween. The holder block 20 can be provided with a resilient tab 29 opposing the attachment portion of the body block for engagement with a connector lug 12 of the testing apparatus, sandwiching the connector lug 12 between the attachment portion 15 of the body block 14 and the holder block 20. Flanges of the holder block 20 provide lateral support for the cantilevered portion 14' of the body block. Contact tip 18 is located on cantilevered portion 14' with high precision through the use of a preload block 140 which is separated from the body block 14 or probe tip sub-assembly 210 after molding.