Pulsars new Heavy Duty security clamps are ideal for automated and remote observatory domes. Made from high quality stainless steel, they remain permanently engaged whilst still allowing free rotation of the dome top. In extreme weather conditions, the dome can be additionally screwed down and secured with the optionally available M8x20 wing screws. We advise the use of these clamps for not only remote use, but also public observatories and schools. They can easily be fitted to exisiting pulsar domes too ! Our HD clamps are supplied in 4pcs.