Horseware Rambo Plus Fly Mask Vamoose in Silver/Purple. The Horseware Rambo Plus Fly Mask Vamoose is the most powerful defence against flies and biting insects. The Fly Mask is treated with Vamoose Insect Control Technology, a synthetically engineered form of Permethrin and a natural yet powerful fly repellent typically used against mosquitos. The Vamoose is bound to the fabric of the mask and is effective for up to 20 washes. The Horseware Rambo Plus Fly Mask Vamoose is made from a textilene outer which is extremely durable, whilst the ear material is made from a soft Polyester mix and all the edging has a soft and comfortable fleece material to prevent rubbing. Read more… The fly mask not only provides ultimate protection from flies it also provides UV Protection from the sun. The Horseware Rambo Plus Fly Mask Vamoose features a fantastic improved design for optimum eye clearance and protection, along with a detachable muzzle for nose protection. The fly mask features adjustable velcro fastenings with elastic to provide some give and comfort while your horse is grazing.