# Zero Lag Indicator Envelope (ZLINDICATORENVELOPE)

> QuantNexus indicator page for a zero-lag indicator envelope.

**Route**: `/quantnexus/indicators/zlindicatorenvelope/`

## What It Does

ZLINDICATORENVELOPE surrounds the zero-lag indicator with upper and lower percentage bands.

## Formula

`Upper = ZLIndicator(period, gainlimit) * (1 + perc / 100)` and `Lower = ZLIndicator(period, gainlimit) * (1 - perc / 100)`

## Parameters

- `period` - default `30`
- `gainlimit` - default `50`
- `_movav` - default `EMA`
- `perc` - default `2.5`

## C++23 API

```cpp
#include <nonabt/indicators/zlindicatorenvelope.hpp>
auto zlEnvelope = std::make_unique<nonabt::ZLINDICATORENVELOPE>(data().close(), 30, 50, "EMA", 2.5);
```

## Common Usage

- Use it to spot extension around the error-correcting baseline.
- Pair it with crossovers or reversion triggers.
- Helpful when you want a lag-reduced envelope for swing systems.