Available space is less and varies due to many factors. A standard configuration uses approximately 8GB to 11GB of space
(including iOS and preinstalled apps) depending on the model and settings.
Preinstalled apps use about 4GB, and you can delete these apps and restore them.

FaceTime calling requires a FaceTime-enabled device for the caller and recipient and a Wi-Fi connection.
Availability over a cellular network depends on carrier policies; data charges may apply.

All battery claims depend on network configuration and many other factors; actual results will vary.
Battery has limited recharge cycles and may eventually need to be replaced by Apple service provider.

 Model Name: Apple Iphone 6s
Brand: Apple
Color: Gold
Size and Weight: Width: 67.1 mm
Height: 138.3 mm
Weight: 143 grams
Depth:7.1 mm
Operation System: iOS 9, upgradable to iOS 13.3
Storage: 32GB
Display: Retina HD display with 3D Touch, 4.7-inch (diagonal) widescreen LCD Multi-Touch display with IPS technology, 1334-by-750-pixel resolution at 326 ppi
Chip: A9 chip with 64-bit architecture, Embedded M9 motion coprocessor
Camera: 12-megapixel camera, Live Photos with stabilization,Autofocus with Focus Pixels, Optical image stabilization (iPhone 6s Plus only), True Tone flash
Wide: ƒ/2.2 aperture
Power and Battery:  TNon-removable Li-Ion 1715 mAh battery (6.91 Wh)
Wireless charging (works with Qi chargers10) Charging via USB to computer system or power adapter
Sensors: Face ID, Barometer,Three‑axis gyro, Accelerometer, Proximity sensor and Ambient light sensor
FaceTime HD Camera: 5-megapixel photos
Touch ID: Fingerprint sensor built into the Home button