Amesbury Truth modern hardware active Signature series sliding door locking handle - Limited Inventory, Discontinued by Truth 

Application: Sliding Glass Patio Door, Lock Centered
Function: Active, Keyed
Keyway: Schlage SC1, 5 pin 
Plate Style: Radius / Round Top 
Plate Width: 1 inch (25.4mm)
Plate Length: 10 inch ( 254mm)
Screw Hole Spacing: 3-15/16 inch (100mm) 

Note: Vinyl patio doors normally use off centered locks, this one the lock is in the center, normally used on wood or aluminum doors