a small immersion heater is rated at 350 w

A Small Immersion Heater Rated at 350W: Practical Choice for Many Export Applications
When you're sourcing small immersion heaters for export markets, especially for regions with 110–120V systems or applications that require precise, low-power heating, the 350W rating has become one of the most commonly requested specifications in recent years.
A 350-watt immersion heater sits in a sweet spot - powerful enough to do meaningful work, yet small and energy-efficient enough to be welcomed in many countries with strict household electrical limits, rental properties, student accommodations, laboratory use, and various light industrial applications.
Typical Real-World Applications
From our experience serving customers in North America, Southeast Asia, Middle East, and parts of Europe, 350W small immersion heaters are most frequently used in these scenarios:

Travel-size baby bottle warmer / milk warmer
Many young parents in the US, Canada, and Australia prefer 350W models because they heat 150–250ml of milk/water quickly (usually 3–6 minutes) without tripping 15A circuit breakers common in hotel rooms or Airbnb rentals.
Single-serve coffee/tea travel mug heater
Popular among office workers and truck drivers in the Americas who want to keep coffee at drinking temperature (around 55–65°C) for hours without using a full 800–1000W travel kettle.
Small laboratory water bath & reagent heating
Universities and testing labs often specify 300–400W range because these heaters produce less thermal fluctuation and are easier to control with simple thermostats or basic PID controllers.
Aquarium & turtle tank heater backup
In many tropical countries where room temperature is already 26–30°C, a 350W heater is more than sufficient for 50–120 liter tanks and gives better temperature stability than oversized 500–800W units that cycle too frequently.
DIY sous-vide & fermentation projects
Homebrew beer, yogurt makers, and low-budget sous-vide enthusiasts frequently choose 350W because it's easier to achieve stable low-temperature control (especially when paired with cheap 10A SSRs).

Technical Points Importers Usually Care About
When writing your product listing or replying to inquiries, these are the details experienced buyers almost always ask:

Sheath material & grade - 304/316L stainless steel is the baseline expectation. Titanium or Incoloy 800/840 is a frequent upgrade request for harder water areas
Thread size - BSP 1¼", 1½", 2" and NPT 1", 1¼", 1½" are the most common. Many US buyers still strongly prefer NPT
Thermostat type & range - Capillary thermostat 30–85°C or 0–120°C is standard. Electronic thermostat with ±1°C accuracy is becoming a popular mid/high-end option
Power tolerance - ±5% or ±10%? Most buyers accept ±10%, but lab & medical customers usually insist on ±5%
Length under flange - 150mm, 200mm, 250mm and 300mm are the best-selling lengths for small power units
With or without indicator light - Surprisingly, many American and Canadian customers still prefer models with a visible neon/LED indicator
Grounding - Make sure the grounding terminal is clearly visible and meets UL/IEC requirements (very important for North American market)
Waterproof rating of terminal box - IP54 is usually sufficient, but IP65/IP67 is preferred for humid environments (Southeast Asia, coastal Middle East)

Quick Comparison: 350W vs Neighboring Power Ratings

200–250W → too slow for most users, mainly used in 5–20L very small tanks or extremely power-restricted locations
350W → best balance of speed & control for 20–120L applications
500–800W → faster heating but much shorter on/off cycles → more temperature fluctuation, higher possibility of nuisance tripping in weak circuits