The Belri brand was produced by a company that I knew (perhaps wrongly) as Belleri. As far as I was aware, Belleri’s main product line was handlebars and handlebar stems. Belleri produced bars branded as ‘Belleri’ and ‘Belri’. I mainly came across them on lower end bicycles from the Peugeot and Gitane families of companies. In particular, in the 1970’s, French bicycles often had 25.0mm steerers and needed stems to fit, and the only choice was often a Belleri. Belleri also produced a range of very European shapes of handlebars, these products were like magnets for some of the more eccentric cyclists in the world.

I believe that Belleri were based in Sorbiers, near St Etienne, France.

I would guess that Belleri only produced one model of derailleur and branded it Belri. This derailleur looks, to me, as though it was an opportunistic attempt to cash in on one of the periodic shortages caused by one of the various booms in sales of derailleur bicycles in the USA.