Some rail layouts don't just turn or branch — they cross. This four-outlet flush "X" fitting joins two perpendicular 1.5" OD handrail runs at a single four-way junction, with each of the four tubes sliding in for a flush joint. It's the fitting for gridded rail layouts: a mezzanine or catwalk grid, a network of walkways, a point where multiple runs converge and each has to continue through. The five finishes cover most settings: polished brass for a traditional rail, 304 stainless polished or satin for a modern interior, and 316 stainless polished or satin where salt or chlorine calls for corrosion resistance. Being a four-way fitting, it does more at one junction than an elbow or a "T," which is why it's the piece to reach for wherever two runs genuinely cross. Note the OD won't interchange with 1.67" or 2" tubing.