Amazon has Adams Flea & Tick Collar for Large Dogs, 2 Pack Grey One Size on sale for $18.10
Shipping is free w/Prime
PREVENTS INFESTATIONS: Kills fleas and ticks for up to 6 months.
MOSQUITOES TOO: Repels mosquitoes for up to 6 months.
ONE SIZE FITS ALL: Adjstable and one size fits all — just cut to size.
WATER RESISTANT: Wetting will not impair the collar’s effectivness or the dog’s protection from fleas, ticks and mosquitoes.
12 MONTH PROTECTION: A full year’s protection with two collars in each tin.