Set of four joint bolts for use with Ecotone aluminium poles to prevent pole folding.
Full sets of poles available here: https://british-trust-for-ornithology.myshopify.com/products/ecotone-set-of-two-aluminium-poles
Additional top sections available here: https://british-trust-for-ornithology.myshopify.com/products/ecotone-aluminium-pole-additional-top-section-set-of-two