Playbooks

Not in any team playbook.
Double Ins is a trips-based passing concept out of Shotgun Y Off Trips Close that isolates the two inside receivers on a matching in-breaking route pattern while the single receiver on the backside runs a deep out to hold the corner. The outside trips receiver clears vertically before snapping his route back across the field, the slot runs a shallow in under him, and the TE releases into a flat/curl read against the boundary while the RB stays in to protect. This is a man beater built to create natural picks and rubs between the two ins, with the primary read starting on the deep in from the slot working back to the shallow in underneath if the linebackers sink into the throwing lanes.
Man coverage with no safety help over the middle is the biggest vulnerability here, since the natural picks from the two crossing ins will consistently separate defenders trailing in man technique. Cover 3 with a sinking middle linebacker can take away the shallow in, so read the flow of the linebacker level presnap to anticipate where the throwing window will be. Watch for a user-controlled defender sitting in the shallow zone or lurking near the ins, as that is the most common way this concept gets jumped and picked off. Blitzes that bring extra rushers off the edge opposite the trips can rush the quarterback before the deep in fully develops, so identify overload pressure looks presnap and consider a quick hot route to the single receiver. Cover 2 shells with deep safeties sitting on the outside can bait a throw to the shallow in, but the underneath linebackers dropping into those lanes are the real determining factor on whether this concept stays open.
Presnap, identify if the defense is showing man coverage by checking for a single high safety and tight corner alignment on the trips side, since the natural rub created by the two ins will beat man leverage badly.
If you see zone drops with linebackers sitting on the shallow in route, hold your eyes on the deeper in from the slot for a hole shot behind the underneath defenders.
Use this on second and medium to long third down since the routes take a full beat to develop and need room to work the middle of the field.
Hot route the single receiver's deep out into a quick hitch or slant if you are facing a hard corner blitz off that edge, since he is otherwise uninvolved in the primary read.
Pair this with Slot Out or TE Whip from the same set to keep the defense guessing between quick underneath throws and the deeper in-breaking concept, forcing linebackers to widen their drops.