Dry rubs and marinades only season the outer layers of a cut of meat. In order for any marinade to penetrate deeply, you need a delivery system. That’s where marinade injectors come in. Originally popularized with the advent of Cajun-style turkey fryers decades ago, they are useful for virtually any domestic meat or game preparation, from venison and wild pig to duck and dove. Here’s what to look for in this underutilized tool of the culinary arts.