Ruby glass was a staple at the Palace workshops. Moss, Graham and Tsang, in A Treasury of Chinese Snuff Bottles, Vol. 5, Glass, p. 18, write that during the early years of the Imperial glassworks, from 1696 into the beginning of the Qianlong period, it might have been a closely guarded secret at the Imperial glassworks, slowly leaking out to other workshops over time.
The use of ruby-red glass in combination with the mask-and-ring handles and broad mouth with rolled lip indicate Palace workmanship. The unusual tree-like combination of the four-pronged tails of the dragons, resembling bifurcated or trifurcated tails, and position of the rear legs is an archaistic detail associated with the Qianlong Palace atelier.
See Moss, Graham and Tsang, A Treasury of Chinese Snuff Bottles, Vol. 5, Glass, no. 835, for a carved aquamarine-blue glass bottle with similar treatment of the chi dragons.