SummaryI'm still learning my way around my new dual-extruder Raise N2, but one thing that quickly became obvious is that the sharp angle that the filament makes into the extruder tower when using the built-in spool holders is problematic in that it can lead to breakage of brittle material or slippage of soft material. This Thing allows fitment of 4mm PTFE tubing to establish a minimum filament bend radius. Works with top cover on or off.