Editing String trimmer (section)

== Power and emissions ==
[[File:String trimmer - saitama - 2018 May 4.webm|thumb|thumbtime=2|A man using a string trimmer in [[Saitama prefecture|Saitama]], [[Japan]]]]

[[Gasoline]]-engine powered trimmers usually have a minimum of {{cvt|21|cc|cm3 cuin}} displacement motors. At this size they can easily turn {{convert|2|mm|adj=on}} line and some have nylon blades as accessories to the line-reel. A {{cvt|32|cc|cm3 cuin}} engine can swing a {{convert|2.75|mm|abbr=on}} line and often has metal-blade accessories. Most trimmers use [[single-cylinder engine]]s (particularly [[two-stroke engine|two-stroke]]) and require gasoline mixed with oil. Due to pollution laws [[four stroke engine]]s are becoming more popular, particularly in the commercial market. Manufacturers include [[Honda]], [[MTD Products|MTD]] and [[Craftsman (tools)|Craftsman]]. Companies such as [[John Deere]] carry low-emission two-stroke engine trimmers. [[Stihl]] manufactures a hybrid four stroke engine trimmer that still requires oil to be pre-mixed into the fuel.{{CN|date=October 2024}}

Electrically powered string trimmers produce zero emissions at the point of use, are more efficient, and eliminate risks from spilled gasoline.<ref name=":0">{{Cite web |last=Hope |first=Paul |date=2023-06-07 |title=5 Green Reasons to Choose Battery-Powered Lawn Tools |url=https://www.consumerreports.org/home-garden/reasons-to-choose-battery-powered-lawn-tools-a1182121491/ |access-date=2023-06-17 |website=Consumer Reports |language=en-US}}</ref> However, they are typically less powerful and robust than gasoline-powered units; normally they are limited to {{convert|2.5|mm|abbr=on}} maximum diameter nylon because of their lower power output (400 to about 1200 watts). Gas-powered string trimmers are not regulated to have emission-capturing technology.<ref name=":0" />

Mains-powered string trimmers have the advantage of being very light, easy to maneuver and easy-to-operate. However, both the power cord and total cord length limit them. Recharge time for a battery model using small or large sealed lead acid, nickel metal hydride, or lithium-ion batteries is typically several hours; some models offer a quick-charge option of as little as half an hour, or a removable battery pack. {{CN|date=October 2024}} 

Propane-powered string trimmers were also manufactured by Lehr.<ref>{{cite web|url= https://www.popularmechanics.com/home/tools/reviews/a4561/4332413/ |last=Plueddeman |first=Charles  |date=1 October 2009|website=popularmechanics.com |title= 10 Most Brilliant Products of 2009: Lehr Propane Trimmer|access-date=15 May 2020}}</ref><ref>{{cite web|url= https://www.grit.com/tools/lehr-propane-powered-eco-trimmer-clean-green-and-mean |last=Will |first=Hank  |date=24 August 2009|website=grit.com |title= LEHR Propane Powered Eco Trimmer: Clean, Green and Mean|access-date=15 May 2020}}</ref><ref>{{cite web|url= https://www.latimes.com/home/la-hm-majordomo2-2009may02-story.html |last=Neil |first=Dan  |date=2 May 2009|website=[[Los Angeles Times]] |title= Yard work cleaned up|access-date=15 May 2020}}</ref>