Either a 336 gm or 1.8kg pail of rat bait. Contrac All-Weather Blox is an anticoagulant rodent bait for the control of rats and mice. Single-feed bait requires just one feed for it to kill rats and mice. This toxicant is less toxic to non-target animals in primary and secondary poisoning situations than other single-feeding anticoagulants. Mould and moisture resistant.